International law is universal in theory, but in practice, its effectiveness varies across different states and their different institutional contexts. This phenomenon of diversity has stimulated the field of comparative international law, which studies “how actors in different legal systems understand, interpret, apply, and approach international law”.Footnote 1 This field also highlights the eternal question of how effective international law truly is, which makes it a project deserving of study now more than ever to safeguard shared values on a global scale.
Situated in this field, this article examines the engagement of Taiwan’s Constitutional Court (TCC) with international law. Specifically, it investigates how international law is understood, interpreted, and applied in the TCC’s decisions. This article contributes to a unique body of work that focuses on the interactions between apex courts in Asia and international law.Footnote 2
It is crucial to establish Taiwan as an important area of study for public international law, despite ongoing contestations regarding Taiwan’s international legal status. Here, several clarifications are necessary to resolve doubts about Taiwan’s relevance to public international law. Taiwan, operating under the name of the Republic of China (ROC), satisfies the traditional criteria for statehood under the Montevideo Convention on the Rights and Duties of States – widely regarded as reflecting customary international law – which include a permanent population, a defined territory, a government, and the capacity to engage in relations with other states. Taiwan’s limited diplomatic recognition stems not from a deficiency in these attributes, but from the political objections of the People’s Republic of China (PRC). Although Taiwan currently lacks universal recognition as a state, recognition is not considered a requirement for statehood under the prevailing declaratory theory of recognition.Footnote 3 At a minimum, Taiwan’s status as an international legal person – capable of bearing rights and obligations under international law – is uncontroversial. Where the PRC’s objections can be countered, Taiwan participates in a number of treaty regimes, though it is pressured to use terminology that is typically not associated with statehood. In other words, whenever international politics permits, Taiwan undertakes and fulfils its international legal obligations, just as other states do. Even in other treaty regimes that Taiwan is unable to participate in, it voluntarily establishes domestic institutions to enforce relevant international norms, particularly in the area of human rights. The TCC and ordinary courts in Taiwan also reference international law, just as courts in many other countries do. Accordingly, whether Taiwan complies with international law – and how international law influences Taiwan’s practices, including judicial practices – constitutes a valid and necessary subject of empirical inquiry in the field of international law.
Drawing on insights from the case study of Taiwan, this article contributes to public international law by developing a typology that captures how domestic courts engage with international law to varying degrees in terms of the legal authority and transformative potential of international law. After all, not all citations are equal in function. Different kinds of citations serve different functions – when courts cite international law, it may be treated and enforced as legally binding, or it can be seen as merely one of many persuasive, non-binding sources of law. Moreover, some citations nominally reaffirm and legitimise existing state practice, while others possess the transformative power to alter state practice. Different citations, therefore, reflect different degrees of engagement in terms of the authoritative weight and transformative potential of international law in domestic practice. Furthermore, the degree of engagement may evolve over time, sometimes intensifying or sometimes diminishing. These variations, along with their temporal element, are significant yet often overlooked.
To illustrate this complexity, the proposed typology categorises international law citations along two analytical dimensions: legal effect (determining whether international law is regarded as binding – either advisory or authoritative) and impact level (determining whether international law is used to reaffirm or alter existing constitutional jurisprudence, or guide the future policies – either reaffirming, formative, or prospective).
This typology enables this article to illustrate varying degrees of engagement with international law across different cases brought before the TCC. Based on this typology, this article finds that the TCC’s international law citations have primarily been advisory and either reaffirming or prospective. However, in recent years, there has been an increase in formative citations, where international law significantly influences the Court’s jurisprudence, along with a few authoritative citations in which international treaties are regarded as legally binding. Thus, the TCC’s previously thin engagement with international law is evolving and has the potential to continue to develop more substantively.
This article builds on, but moves beyond, Wen-Chen Chang’s account of convergence between Taiwan’s constitutional jurisprudence and international human rights law.Footnote 4 It offers a more nuanced analysis by distinguishing between varying degrees of judicial engagement with international law, and goes further to incorporate a temporal dimension so as to highlight the evolving process of the Court’s engagement with international law.
Beyond this particular case study, this typology can be tested broadly. It seeks to differentiate various types of international law citations and the different degrees of engagement behind each citation. If we treat all international law citations as the same without recognising their distinct functions, it would be impossible to discern how meaningfully a court interacts with international law and how that interaction changes over time. This typology contributes to public international law by providing an analytical tool by which the authoritative weight and potential transformative impact of international law in Taiwan and beyond can be evaluated.
Situated in the field of comparative international law, this article examines how international law – not including the domestic laws of other countries – is understood, interpreted, and applied in Taiwan. By contrast, David Law and Wen-Chen Chang approach Taiwan’s judicial engagement with external norms through the lens of comparative constitutional law, treating international law and foreign law as a single category.Footnote 5 Taking a different approach, this article is concerned with judicial behaviour in the context of international legal compliance. It draws a distinction between international law and foreign law, focusing exclusively on the former: while states are not legally bound by the domestic laws of other nations, they are bound by obligations arising from treaties and customary international law. When a national court cites international law, it should not merely be viewed as borrowing something foreign; it constitutes an act of compliance with the state’s international legal obligations.
The structure of this article is as follows: Section I examines how international law is treated within the ROC constitutional framework, presenting the constitutional context in which international law operates. Section II surveys Taiwan’s formal commitment to international treaties, including those historically ratified by the ROC government as well as those adopted more recently by democratic Taiwan. It outlines the international legal obligations that Taiwan undertakes while emphasising the challenges Taiwan faces in joining treaty regimes.
Section III provides an overview of the TCC to establish the institutional context in which international law is approached in practice. It then examines the constitutional cases that cite international law and introduces a typology that categorises these citations along two dimensions: legal authority and impact level. This typology approach is used to examine the development of international law’s authority and influence in Taiwan’s constitutional jurisprudence over time. It highlights the TCC’s evolving approach to citing international law, particularly with regard to human rights treaties, which is the most prominent aspect of the TCC’s practice.
Section IV, in analysing the TCC’s engagement with international law, evaluates the Court’s rationale in three aspects: practical, normative, and strategic. Particularly, it investigates the rationale behind the Court’s approach, with special attention to why international treaties are often referenced not as binding legal norms, while also identifying instances where they are treated as such. It finds that the TCC’s attitudes towards international law – paradoxically both open-minded and reserved – reflect the dual realities of Taiwan’s exclusion from international organisations and the Justices’ cosmopolitan perspectives.
Section V examines the heated debate in Taiwan over the status of international human rights law that arose upon Taiwan’s adoption of the International Covenant on Civil and Political Rights (ICCPR) and the International Covenant on Economic, Social and Cultural Rights (ICESCR) in 2009, which marked a watershed moment in Taiwan’s incorporation of international human rights law into domestic law. This debate is not merely academic; different positions result in different relationships between ordinary courts and the TCC. They undoubtedly lead to varying levels of rights protections in Taiwan, as well as varying degrees of judicial engagement with international law.
To analyse the TCC’s jurisprudence and to develop the proposed typology of international law citations, I rely on doctrinal analysis of the Court’s judgments as the primary source material. To contextualise and supplement these findings, I draw on the extensive fieldwork and interviews conducted in Taiwan during the early years following Taiwan’s ratification of the ICCPR and ICESCR. I also draw on ongoing informal discussions and observations in Taiwan to maintain current insights.
Interviewees were selected through purposive sampling based on their expertise in Taiwan’s engagement with international human rights law, including local stakeholders directly involved in legal developments in this field, such as legal scholars, advocates, lawyers, prosecutors, judges, and Justices of the TCC. With the exception of a few individuals who did not respond to my inquiries, most of those contacted agreed to participate. In total, from 2012 to 2013, I conducted 40 interviews with 29 interviewees (some of whom were interviewed more than once). Interviews typically lasted between 60 and 120 minutes and followed a semi-structured format to allow for the flexibility of pursuing emerging lines of inquiry. The interview questions varied across interviewees depending on their professional backgrounds, but they generally included how interviewees perceive and approach international human rights norms, their reasons for drawing on these norms in their respective fields of work, and their observations on both the progress and shortcomings in the process of Taiwan’s adoption of human rights treaties. The interview data were analysed using narrative analysis to explore interviewees’ attitudes towards international norms and the meanings they attach to these norms in their professional work.
The identities of all interviewees have been kept anonymous to ensure confidentiality. The qualitative research was determined by the University Committee on Activities Involving Human Subjects at New York University to be exempt from full Institutional Review Board review under the U.S. Federal Policy for the Protection of Human Subjects (45 CFR §46.101(b), paragraphs 2 and 3), as it involved minimal-risk interviews with professionals and incorporated appropriate safeguards for confidentiality. Informed consent was obtained from all participants. I do not claim to have interviewed all relevant actors; however, the number and diversity of interviews conducted were sufficient to corroborate key information across sources to identify important actors and events. Nor do I claim that the selection of interviewees is representative. Rather, the qualitative component is intended to complement the doctrinal analysis in this article by providing a context-sensitive account of how international human rights norms are perceived, interpreted, and applied in Taiwan.
I. Positioning international law within Taiwan’s constitutional framework
International law receives limited attention in the ROC Constitution. The Constitution addresses only the process of concluding treaties, with an emphasis on the separation of powers among the President, the Executive Yuan (the executive branch), and the Legislative Yuan (the legislative branch). According to the Constitution, the President has the authority to conclude treaties, while the Executive Yuan is responsible for initiating and reviewing them, which must be submitted to the Legislative Yuan for approval.Footnote 6
In 1993, a peculiar yet significant question concerning the definition of a “treaty” arose when the Taiwan government started signing agreements with the PRC through intermediary, semi-official organisations. These agreements ushered in practical cooperation across the Taiwan Strait for the first time since 1949. Were they akin to treaties signed with foreign countries, and should they thus be classified as “treaties”? In Interpretation No. 329,Footnote 7 the TCC excluded Beijing–Taipei agreements from the category of “treaties”, recognising the unique relationship between Taiwan and mainland China as distinct from Taiwan’s relations with other states.
The Court further defined a “treaty” in the constitutional sense as an international written agreement between the ROC and other states or international organisations. These international agreements, regardless of their designation (treaty, convention, agreement, etc.) and regardless of whether they include ratification clauses, require the approval of the Legislative Yuan (unless pre-authorised by law, pre-approved by the Legislative Yuan, or in accordance with existing domestic laws). Importantly, the Court concluded that treaties ratified through this process attain the same legal status as domestic laws.
According to this interpretation, a treaty that satisfies all the constitutionally required procedures should automatically acquire domestic legal status in Taiwan, without the need for a legislative transformation into domestic law. This, in theory, reflects a monistic approach,Footnote 8 where the international and domestic legal systems are treated as a unified entity. However, this monistic approach is complicated by the reality of Taiwan’s exclusion from many treaty regimes.
Taiwan’s general lack of recognition by states and international organisations, a condition often referred to as “international isolation” in Taiwan, poses a significant barrier to its participation in multilateral and bilateral treaties. Take, for example, Taiwan’s attempt in 2009 to ratify the ICCPR and the ICESCR.Footnote 9 Despite not being a member of the United Nations (UN), Taiwan sought to deposit the instruments of ratification, but the UN Secretariat rejected Taiwan’s request. The rejection would have left the status of these treaties ambiguous in Taiwan due to the incomplete deposit process. In anticipation of such challenges, Taiwan developed an innovative strategy to integrate these treaties domestically. Taiwan’s Legislative Yuan enacted a law to implement the ICCPR and ICESCR,Footnote 10 granting domestic legal status to the human rights provisions in the two covenants. Furthermore, given Taiwan’s inability to be monitored by the treaty bodies, the law demanded that the government establish a review system to monitor treaty implementation.Footnote 11 This model of using an “implementation law” to give human rights treaties the same effect as domestic legislation, initially applied to the ICCPR and ICESCR, has been expanded to serve as the framework for Taiwan to integrate additional treaties into domestic law, including the Convention on the Elimination of All Forms of Discrimination against Women (CEDAW),Footnote 12 the Convention on the Rights of Persons with Disabilities (CRPD),Footnote 13 the Convention on the Rights of the Child (CRC),Footnote 14 and the UN Convention against Corruption (UNCAC).Footnote 15
The “implementation law” model has been developed to tackle the challenges in treaty deposit or exchange that Taiwan faces. In this model, treaties are granted domestic effect on a case-by-case basis. In other words, although Taiwan’s legal system is theoretically monistic when it comes to international law, it nevertheless often utilises a dualistic approach by converting treaties into domestic law through specific legislation.
To provide a more systematic solution to Taiwan’s challenges in treaty deposits, the 2015 Law Governing the Conclusion of Treaties was enacted.Footnote 16 This law specifies that in “special circumstances” – when the exchange or deposit of ratification instruments is impractical – the President may directly promulgate the treaty, bypassing these external procedures. Under such “special circumstances”, treaties that have completed the necessary domestic processes (including legislative approval and presidential promulgation) are automatically regarded as part of the domestic legal system, removing the need for exchange or deposit.
The role of customary international law in Taiwan also merits attention for our background. Although the Constitution and constitutional decisions do not specify the status of customary international law, scholars generally agree that it is binding on Taiwan and can be directly applied in domestic courts.Footnote 17
This section outlines the basic positioning of international law under Taiwan’s constitutional and legal framework. Yet, many significant questions remain. What is the legal ranking of international law in relation to constitutional norms as well as domestic legislation? What are the constitutional implications of international law’s place within Taiwan’s legal hierarchy? These issues will be further explored in the following sections.
II. Taiwan and international treaties
A. Historical ROC’s ratification of treaties before 1971
After World War II, the Allies instructed Japanese forces in Taiwan to surrender to Generalissimo Chiang Kai-shek. Across the Taiwan Strait, the situation in China descended into a civil war between Chiang’s Nationalist Party (KMT) and Mao Zedong’s communist forces. Following Mao’s victory, the Chinese Communist Party established the PRC in 1949. Chiang’s ROC government was forced to retreat to Taiwan, which had been under Chiang’s de facto occupation since 1945. The ROC government in Taiwan at this time – despite losing effective control over mainland China – asserted itself as the sole legitimate representative of the Chinese state. Remarkably, it retained China’s seat at the UN and other intergovernmental organisations for more than two decades after the PRC’s establishment.
In October 1971, the United Nations General Assembly adopted Resolution 2758, recognising the PRC as the sole government representing the state of China and expelling the representatives of Chiang Kai-shek from the organisation. The ROC government, before being de-recognised at the United Nations, signed and ratified several important UN treaties as the government of China. This article uses the term “historical ROC” to refer to the ROC during this period, when it claimed to represent the state of China, in order to distinguish it from democratic Taiwan, which focuses on representing the people of Taiwan.
Among the treaties ratified by the historical ROC were the Convention on the Prevention and Punishment of the Crime of Genocide (1951), the International Convention on the Elimination of All Forms of Racial Discrimination (1970), various International Labour Organization (ILO) Conventions,Footnote 18 and some less notable treaties.Footnote 19 The ROC signed the ICCPR and the ICESCR in 1967, but did not proceed to ratification before the UN shifted its recognition to the PRC government.Footnote 20
Notably, while the historical ROC purported to apply these human rights treaties to Taiwan, they were merely window dressing. In one of the longest martial law regimes in the world, the KMT party-state established a wide range of repressive institutions in Taiwan to undermine rights protections and democratic institutions under the guise of protecting state security and preventing communist rebellion.
B. Taiwan’s adoption of treaties
In the years following 1971, the ROC government in Taiwan was de-recognised by numerous international organisations and lost diplomatic relations. In light of these diplomatic setbacks, the authoritarian government, which still aimed to compete with the PRC government for China’s representation, became hesitant to pursue international participation.
This international policy, however, underwent a significant shift in the 1990s during the process of democratisation. The leaders of democratic Taiwan, including former president Lee Teng-hui and his successors, adopted a proactive and pragmatic approach to Taiwan’s international engagement in response to public sentiment and the country’s new challenges in a globalised world. While Taiwan’s democratic government retains the official name “ROC”, it no longer seeks to compete with the PRC as the legitimate government of the Chinese state but instead focuses on representing the Taiwanese people.
Taiwan has the capacity for international relations like any other sovereign state, and fulfils corresponding roles in intergovernmental organisations, but it often faces barriers to entry, mainly due to opposition from the PRC. Nonetheless, it has made some strides in securing a limited role in select intergovernmental organisations. This has been achieved through challenging negotiations and creative solutions, including developing unique nomenclatures for Taiwan. For example, Taiwan joined the World Trade Organization (WTO) as the “separate customs territory of Taiwan, Penghu, Kinmen, and Matsu” (referred to as “Chinese Taipei”).
In cases where Taiwan is officially a member, such as with the WTO, the obligations under these treaties are clearly binding on Taiwan. However, the situation becomes less straightforward for treaties to which Taiwan is not a party. In at least one case, for example, the TCC refrained from citing a treaty that Taiwan had not ratified.Footnote 21 Yet, despite such limitations, the TCC has nonetheless made notable references to international law in its decisions, particularly UN human rights treaties.
Since democratisation, civil society activists and academics have strongly and continuously pushed for Taiwan to adopt international human rights norms. This advocacy gained considerable momentum during President Chen Shui-bian’s administration (2000–2008). In 2007, his government ratified CEDAW, making it the first human rights treaty adopted by democratic Taiwan, although Taiwan’s attempt to formally submit the ratification instruments to CEDAW was unsuccessful.
When President Ma Ying-jeou took office (2008–2016), his administration further advanced the initiative to integrate human rights treaties by accepting the ICCPR and the ICESCR in 2009. This marked the first instance in which an accompanying implementation law was enacted to explicitly confer legal binding force on a treaty. Following this precedent, in 2011, the Legislative Yuan passed an implementation law for the CEDAW (which Chen Shui-bian’s administration had ratified four years earlier) to clarify the treaty’s legal authority. Taiwan also adopted the CRC and CRPD in 2014 and the UNCAC in 2015, enacting implementation laws for each of these treaties. These implementation laws provide international treaties with domestic legal status, despite Taiwan not being recognised as a formal member of the respective treaty regimes.
Currently, Taiwan is considering accepting more human rights treaties, such as the Convention against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment (CAT). The legal effects of treaties that Taiwan has neither ratified nor incorporated through domestic legislation should be distinguished from those it has formally accepted. Treaties that Taiwan has not adopted are not considered legally binding on Taiwan; however, to the extent that they contain provisions considered jus cogens (peremptory norms) or have become part of customary international law, Taiwan, like other states, is obligated to comply with these norms.
III. International law citations in Taiwan’s constitutional cases
A. An overview of Taiwan’s Constitutional Court
TCC, formerly referred to as the Council of Grand Justices, is primarily responsible for interpreting the Constitution and unifying the interpretation of laws and regulations. Historically, the Court’s review was limited to assessing the constitutionality of laws or regulations, with its majority opinions rendered as “interpretations” and sequentially numbered since the very first “interpretation” in 1949.
In 2022, the Constitutional Court Procedure ActFootnote 22 introduced significant reforms, transforming the review process into an adjudication-oriented model. Key changes included the incorporation of public hearings to solicit parties’ views, the institutionalisation of professional consultation and the submission of amicus briefs, and the introduction of the constitutional complaint mechanism. This mechanism permits the TCC to adjudicate directly on the constitutionality of rulings made by the apex courts within the ordinary judicial system (i.e., the Supreme Court and Supreme Administrative Court), in addition to its traditional scope of reviewing laws and regulations. Consequently, the TCC’s decisions are now labelled as “judgments”, as opposed to “interpretations”.
The Court should comprise 15 Justices, including two who simultaneously serve as the President (Chief Justice) and Vice President of the Judicial Yuan, Taiwan’s highest judicial administrative body. The Justices are nominated by Taiwan’s President and must be confirmed by the Legislative Yuan. Unlike judges of ordinary courts, who are selected from professional admission exams and typically enjoy lifetime tenure, TCC Justices are appointed to a single, non-renewable eight-year term, with these terms staggered.
The selection of TCC Justices is theoretically drawn from diverse backgrounds, yet in practice, the Court has largely comprised academics and career judges, many of whom have undergone advanced legal training both domestically and abroad. For instance, before seven Justices completed their terms in October 2024, leaving their positions vacant, the Court’s 15 Justices included seven legal scholars, six career judges or prosecutors, and two former lawyers. Among the 15 Justices, four received their doctoral legal training in Germany, one in the United States, one in France, and two in Taiwan. The Court is generally characterised by a high level of education and a scholarly orientation, with a significant number of Justices having received doctorates abroad, particularly from Germany and the United States.
B. Patterns of international law citations in Taiwan’s constitutional cases
By the end of December 2023, there were a total of 25 TCC decisions (majority opinions) that cited international law, primarily focusing on human rights treaties. This number is small compared to the total of over 800 decisions (including interpretations and judgments) that the Constitutional Court had made by 2023. In fact, the first interpretation that mentioned international human rights norms appeared as late as 1995, eight years after the martial law regime was lifted. We also do not know how many cases have involved applicants raising legitimate arguments regarding international law that the Court failed to consider.
Not all 25 instances of the TCC’s citation of international norms are the same. To go beyond the surface-level observation that the Court has referenced international norms in 25 decisions, this article aims to examine the underlying jurisprudential weight and transformative impact of those citations. Specifically, it proposes two dimensions for analysing the TCC’s international law citations. The first dimension evaluates whether the cited international norms are considered legally binding by the Court. Accordingly, this article distinguishes between advisory citations (where international norms are referenced as non-binding, persuasive sources) and authoritative citations (where international norms are referenced as legally binding sources).
The second dimension examines the impact of these citations in the Court’s legal reasoning. Based on the Court’s practices, this article proposes three categories in this dimension: reaffirming citations (which reaffirm legal points already established in Taiwan’s jurisprudence or statutory framework), formative citations (which substantially contribute to shaping judicial reasoning and legal interpretation, rather than merely reaffirming existing principles), and prospective citations (which serve as reference points for guiding future legal actions or reforms, even though they do not directly influence the Court’s reasoning).
Given the two dimensions outlined earlier – legal effect and impact level – this article proposes six distinct types (see Table 1). This analytical classification guides the discussion of the TCC’s international citations in the following sub-sections.
Table 1. Typology of TCC’s international law citations.
Based on the classification earlier, the Appendix provides a detailed examination of the existing international law citations of the TCC as of the end of 2023. As shown in the Appendix, in most of the TCC’s citations, particularly in early cases, the Court often views international norms as advisory rather than authoritative sources, primarily reaffirming the human rights protections already well established in the jurisprudence (advisory & reaffirming). In some instances, while the Court considers international norms to be non-binding, it nonetheless directs future legislative and administrative reforms to align with these norms (advisory & prospective).
However, a notable shift has been observed in recent years. Human rights norms are increasingly being utilised to shape the Court’s jurisprudence, moving beyond mere confirmation of existing constitutional protections (advisory & formative). Additionally, the Court has started to view international norms as a binding source that must be considered (authoritative & formative). These trends are analysed in detail in the following sub-sections.
1. The TCC’s traditional approach to international law: advisory, reaffirming, and prospective citations
The above-mentioned typology reveals that the TCC’s early citations viewed international law as an advisory, non-binding source, a perspective that continues to influence the Court’s practice today. When referencing human rights treaties, the Court often does so in conjunction with other regional human rights standards, such as the European Convention on Human Rights (ECHR), as well as foreign laws, including those of Germany and Japan. While legal norms in Germany and Japan have significantly influenced Taiwan’s legal system through processes of legal transplantation, they are not legally binding in Taiwan. The ECHR is also not binding on Taiwan, except for provisions that qualify as jus cogens or customary international law. This suggests that the TCC treats human rights treaties as similar to foreign law – useful for judicial guidance but lacking substantial legal or constitutional authority (advisory citations).
A case in point is Interpretation No. 392 (1995),Footnote 23 the first TCC decision to cite human rights treaties. This ruling, which initiated ground-breaking reforms towards an adversarial system in Taiwan’s criminal justice, held that only judges – not including prosecutors – should have the authority to decide pre-trial detention. In its reasoning, the Court referenced the ECHR, the ICCPR, and the American Convention on Human Rights (ACHR) together, treating the ICCPR on par with other regional treaties to strengthen its argument. Human rights treaties here are seen as “one of the many sources of reference”, not necessarily as more important than other sources.Footnote 24
Furthermore, the TCC’s references to international law usually do not affect the reasoning or alter the final outcomes of its decisions (advisory & reaffirming). Interpretation No. 392 discussed earlier is one example. Another illustrative case is Interpretation No. 709 (2013),Footnote 25 the Court’s first citation of the ICESCR. In reviewing the Urban Renewal Law, the Court acknowledged that the law’s goal of ensuring an adequate standard of living aligned with the ICESCR. However, it refrained from granting constitutional protection to this right as defined in the ICESCR, and did not use the ICESCR to determine the constitutionality of the Urban Renewal Law.
In some cases, even though the Court views international norms as non-binding, it directs future legislative and administrative reforms to align with these norms (advisory & prospective). For example, in Interpretation No. 549 (2002),Footnote 26 the Court instructs that the Labour Insurance Act should be improved in accordance with “relevant ILO Conventions” as a whole, even though Taiwan is not a party to these conventions.
2. Growing significance of international law: formative citations
In a growing number of cases, international law, although not explicitly recognised as binding by the TCC, has significantly advanced its reasoning, which this article refers to as formative citations. Although there may not always be a clear distinction between formative citations and reaffirming citations discussed in this article, the former tends to substantially develop or alter the Court’s jurisprudence. For example, in interpretation No. 587 (2004),Footnote 27 the Court established a child’s “right to identify his or her blood filiations” as protected by Article 22 of the Constitution – a broad provision safeguarding “all other freedoms that are not detrimental to social order or public welfare”. In this case, the Court drew upon the CRC, which at that time had not yet been incorporated by Taiwan, to support the legal principle of a child’s “right to know his or her parents”. While the constitutional basis for this right was still grounded in Article 22 of the Constitution, no prior jurisprudence in Taiwan had explicitly recognised a child’s right to identify blood relations. The Court’s reference to the CRC significantly advanced the development of this legal reasoning,Footnote 28 even though the CRC was not legally binding in Taiwan at the time of the decision (advisory & formative).
Formative citations have become more pronounced in the TCC’s decisions, especially following Taiwan’s adoption of the ICCPR and ICESCR in 2009. In interpretation No. 710 (2013),Footnote 29 the Court not only referred to the ICCPR but also to the Human Rights Committee’s General Comment – citing the opinion of a human rights treaty body for the first time in constitutional decisions – to support the freedom of movement for individuals who entered Taiwan legally from Mainland China. It also mandated due process procedures for deporting such individuals, referencing the ICCPR and Protocol No. 7 to the ECHR regarding the expulsion of an alien lawfully residing in the state’s territory.
3. Harmonising international and domestic law: authoritative citations
In recent years, the TCC has also begun to consider the legal authority of international law, particularly in relation to domestic law. This shift is evident in Judgment No. 6 of 2022.Footnote 30
This case has its origins in a matter that, although seemingly insignificant, is in reality quite contentious in Taiwan. It addressed the Taiwan government’s controversial decision to lift import restrictions on American meat products containing ractopamine, replacing a complete ban with permitted levels of residual ractopamine. The nationwide permission to import these products ignited significant controversy in Taiwan, prompting many local governments to impose their own bans on meat products with ractopamine. The TCC ruled that establishing permissible tolerance for ractopamine in meat products falls solely within the jurisdiction of the central legislative body, and as a result, local governments do not have the authority to prohibit these products in defiance of the central legislative decision. The TCC noted that in setting ractopamine’s maximum residue limits, the central authority complies with the World Trade Organization Agreements (WTO Agreements) and the Agreement on the Application of Sanitary and Phytosanitary Measures (SPS Agreement), to which Taiwan is a formal signatory. The Court further observed that the restrictions imposed by local governments could negatively affect Taiwan’s foreign trade policy and its obligations under international trade treaties.
Importantly, the Court acknowledged that, while violations of international law do not always equate to direct breaches of constitutional law, it is essential to consider the impact of such international law violations on Taiwan’s international relations and treaty obligations. This consideration is especially relevant to the Court in determining whether legislative control over food safety standards, such as the regulation of ractopamine in meat products, should belong solely to the central authority or be shared with local authorities. In its reasoning, the Court emphasised the necessity to “strive for harmony between international law and domestic law”.Footnote 31
In other words, the TCC clearly recognises the binding effect of international law as a factor that shapes its decision. This authoritative citation signifies a new approach for the Court. This approach extends not only to treaties where Taiwan is a formal party, such as the WTO Agreements, but also to those it cannot join but has incorporated domestically through the “implementation law” framework. Take, for example, in Judgment No. 8 (2022),Footnote 32 the Court notes Taiwan’s status as a non-contracting state to the CRC while also recognising the Convention’s domestic legal effect as a result of the implementation law for the CRC. In this judgment, the Court referenced the CRC, and particularly the CRC’s General Comment, to emphasise that when children are capable of forming their own views, those views must be given serious consideration. The Court stressed the need for an explanation of how children’s opinions are factored into decision-making, to ensure that listening to their views does not become a mere formality. These principles regarding respect for children’s views were not originally inherent in Taiwan’s legal framework. They have gained domestic significance through the Court’s recognition of the CRC as part of domestic law and have meaningfully advanced the jurisprudence (authoritative & formative).
To summarise this section, in the early cases of the Court, international norms were often viewed as advisory rather than legally binding. They typically served to reinforce existing jurisprudence (advisory & reaffirming). Occasionally, the Court has encouraged future legislative and administrative reforms to align with these norms (advisory & prospective). However, in recent years, the Court’s references have evolved. Human rights norms are now increasingly shaping the Court’s jurisprudence (advisory & formative). Furthermore, in a few cases, the Court has begun to recognise international norms as a binding source (authoritative & formative). Although such instances are relatively rare, they suggest a possible future for the Court’s increasing involvement with international norms.
IV Rationale behind the use of international law in Taiwan’s constitutional cases
A. Functions for international law citations: practical, normative, and strategic
Why does the Court reference international norms? The rationale behind the TCC’s citations of international law appears to vary depending on the specific legal context. When Taiwan is a party to a treaty, such as in the ractopamine case involving WTO Agreements,Footnote 33 the Court’s reliance on treaty obligations is readily justified. However, in cases involving treaties to which Taiwan is not a formal member, the reasoning for their reference becomes intriguing. What motivates the TCC to refer to international norms that Taiwan is not officially required to follow? This section explores three potential aspects of the Court’s rationale: practical, normative, and strategic. These aspects are not mutually exclusive.
In terms of their practical role, international norms can address gaps not covered by the domestic legal framework, offering essential guidance on new legal challenges. This utility is evident in unprecedented cases, such as the TCC decision concerning a child’s right to know his or her parents – a concept not previously recognised in Taiwan’s legal system. In such cases, the Court seeks comparative materials, including concrete case studies from international law (as well as foreign law) that can enhance the Court’s reasoning.Footnote 34
The normative appeal of international norms is equally important – if not more so – than their practical benefits. Unlike domestic norms, international treaties have a universal appeal, demonstrated by their broad adoption across many states. This universal acceptance provides normative legitimacy that is significant for Taiwan, which, being excluded from many international treaty regimes, is eager for recognition as a legitimate member of the international community. When discussing human rights treaties, the TCC seems less concerned with whether Taiwan has formally ratified the treaty or implemented it through domestic legislation.Footnote 35 Instead, the focus is on the global support for these treaties, especially from “civilised countries” that are viewed as upholding good human rights practices.Footnote 36 The global consensus appears to automatically justify the adoption of similar standards from the TCC’s perspective, a unique characteristic of international norms that is not found in domestic norms.
One should also consider whether the strategic considerations evident in Taiwan’s attempt to ratify human rights treaties also exist in judicial decision-making. Taiwanese political actors have been driven by a desire for international recognition of Taiwan’s human rights accomplishments, believing that the country’s progress since democratisation would be highly valued and that Taiwan would be seen as a state worthy of respect.Footnote 37 This agenda is often intertwined with strategic thinking that ratification could garner more international sympathy by distinguishing Taiwan from the PRC. Some Taiwanese politicians appear eager to use ratification as a means of asserting Taiwan’s superiority over the PRC in terms of human rights and democracy, thereby deserving support from other democratic nations.Footnote 38 However, there is limited evidence to suggest that these political considerations influence judicial decision-making. Even if they do, the Court is unlikely to acknowledge them in decisions that are intended to be free from such political motivations. At most, one could infer that the TCC, by citing international standards, aims to strategically signal to the global community that Taiwan’s judiciary aligns with those of “civilised nations” in upholding international human rights.Footnote 39 This strategy could improve the Court’s reputation.
B. Composition of courts and judicial processes as factors influencing TCC’s international law citations
As Law and Chang argue, several important factors play a crucial role in shaping judicial engagement with foreign law, including the composition and staffing of the court, as well as the level of expertise in foreign law possessed by judges and academics.Footnote 40 Similarly, to understand how international law citations are incorporated into the TCC’s decisions, we must also consider the composition of the bench. As previously mentioned, the TCC is primarily composed of legal academics and career judges, many of whom have received advanced legal training either domestically or internationally. The advanced educational background and scholarly orientation of the Justices enable them to ground the Court’s research and deliberations in academic insights and legal principles from both Taiwan and foreign jurisdictions.
The methods and processes of the Court’s deliberation should also be considered. When formulating a ruling, the Justices, aided by law clerks, seek to conduct comprehensive research and identify all pertinent materials, with a primary emphasis on both domestic jurisprudence and foreign law.Footnote 41 Since the Court’s deliberation is a dynamic process focused on persuading one another on the bench, each Justice seeks to contribute through thorough researchFootnote 42 – research that often draws upon experiences beyond Taiwan, especially in Germany and the United States, where many of the Justices obtained their advanced legal training.
The TCC’s law clerks are also expected to hold at least an LL.M. degree, whether domestic or foreign, and to be capable of researching foreign law.Footnote 43 In the research process, in addition to comparative constitutional law, international and regional human rights jurisprudence are also examined.Footnote 44
Law and Chang observe that the educational backgrounds of the TCC Justices appear to influence the foreign legal sources they cite, particularly in shaping a preference for either German or American constitutional jurisprudence.Footnote 45 But what about international law? While many Justices are experts in constitutional law and comparative law, relatively few specialise in international law.Footnote 46 However, this has not prevented the Court from referencing international legal sources.
This article does not posit a causal or correlational relationship between academic background in international law and citation practices. Justices without formal training in international law may well acquire relevant knowledge through professional experience and scholarly engagement. The more salient point is that the TCC justices, as a collective, are highly educated and rigorously trained, and are therefore fully capable of engaging with international legal jurisprudence. Moreover, as discussed earlier, their engagement with international law is motivated by a range of practical, normative, and strategic considerations that extend beyond individual expertise.
It is crucial to note that while only slightly more than two dozen TCC decisions have officially cited international norms by 2023, the scope and depth of the Court’s discussions often go beyond what is captured in the writing of the decisions.Footnote 47 Before the 2022 reform, TCC’s majority opinions, noted for their brevity, were subject to a comprehensive and laborious deliberation process. Every line was carefully examined, requiring agreement to achieve the necessary two-thirds majority. In instances of disagreement, certain sentences and references were frequently omitted to achieve consensus. Consequently, only elements considered essential were included in the majority’s final text.Footnote 48 It would not be surprising if the majority opinion omits international citations when there is no consensus among all Justices regarding such references. It is understood that Justices have the freedom to discuss these aspects of international law in their individual concurring or dissenting opinions.
Indeed, a review of the concurring and dissenting opinions reveals that international human rights treaties have been increasingly considered by individual Justices in recent years, particularly following Taiwan’s ratification of the two covenants in 2009. Since then, these opinions have frequently referenced international and regional human rights norms, especially the Universal Declaration of Human Rights (UDHR), ICCPR, ICESCR, ECHR, CEDAW, and CRC, among others.Footnote 49 Individual Justices have also begun to reference the General Comments from the treaty bodies of the ICCPR and ICESCR, demonstrating knowledge of the jurisprudence developed by international experts within the UN treaty system.
Looking ahead, the TCC’s 2022 reform could gradually influence both how the Court interacts with international law and how this interaction is presented in its decisions. This reform streamlines the formation of a majority opinion by lowering the threshold from two-thirds to a simple majority, theoretically making consensus in decision-making easier.Footnote 50 Additionally, the Court’s rulings have evolved to be more detailed and expansive. In the future, reasoning based on international law is likely to be included in decisions even without the backing of two-thirds of the Justices. This potential shift would facilitate the expression of judicial views on the role and significance of international law, both in the majority opinion and in separate concurring or dissenting opinions.
V. Status of international human rights law
The TCC has recently demonstrated a greater willingness to engage with international law substantively, and even to “strive for harmony between international law and domestic law”,Footnote 51 but several important questions remain unresolved, especially in situations where achieving harmony between international and domestic law proves challenging. Key issues include whether international law should be regarded as superior to domestic laws and whether international law, especially fundamental human rights norms or jus cogens, can reach constitutional status. These questions have sparked a diverse and interesting scholarly debate in Taiwan, with a focus on the status and ranking of the ICCPR and the ICESCR within Taiwan’s legal hierarchy following their ratification.
Much is at stake in this debate. In Taiwan, only the TCC has the power to invalidate domestic laws that conflict with the Constitution, while ordinary courts – including civil, criminal, and administrative courts – do not possess this authority. When a judge in an ordinary court believes that a law before them infringes on constitutional human rights protections, they cannot nullify it. Instead, they may suspend the trial proceedings sua sponte and petition the Constitutional Court to declare the law unconstitutional. Alternatively, if feasible, they can interpret the law in a way that complies with constitutional standards to avoid the need to request the Constitutional Court to invalidate the law.
One can envision various scenarios based on differing views regarding the hierarchy of human rights treaties in Taiwan. If the ICCPR, ICESCR, and other international human rights treaties ratified by Taiwan are considered superior to domestic laws, ordinary courts would be obligated to uphold these protections, either by dismissing conflicting domestic laws as subordinate to human rights treaties or by interpreting them in line with human rights standards. This could enable ordinary courts to disregard domestic legislation that conflicts with international human rights norms, without requiring the Constitutional Court’s intervention.
If international human rights protections are considered to have acquired constitutional status, the Constitutional Court would be required to apply them in its decisions, potentially altering the scope and content of rights protections under Taiwan’s constitutional framework. Moreover, ordinary courts may need to refer conflicts between domestic laws and human rights treaties to the Constitutional Court for resolution (if they cannot interpret the laws in a manner that complies with constitutional standards).
Therefore, these questions about the status of international human rights protections are not merely academic. Various perspectives can result in differing levels of rights protections in Taiwan and can also affect the power, responsibility, and relationship between ordinary courts and the Constitutional Court. These questions are highly debated among scholars.Footnote 52 Various viewpoints are surveyed and summarised in the following. While the discussion primarily focuses on human rights treaties, the debate also sheds light on broader questions about how international law is understood in Taiwan’s legal system.
A. International human rights treaties vis-à-vis domestic laws
On one end of the spectrum, a reserved stance views international law no differently from domestic law, suggesting that both should, at least in principle, hold equal status without one being superior to the other. From this standpoint, existing domestic laws that contradict human rights treaties would remain valid until amended or repealed by the Legislative Yuan. Certain established doctrines on conflicts of laws, including lex posterior derogat legi priori (later laws abrogate prior contrary laws) and lex specialis derogat legi generali (specialised laws prevail over general laws), may apply depending on the circumstances. Under these doctrines, whichever laws are later in enactment or more specific in application would take precedence, whether they are international or domestic.
Many Taiwanese scholars, however, advocate a contrasting view, arguing that the human rights protections outlined in the ICCPR and ICESCR should always take precedence over conflicting domestic laws. Several arguments support this position. First, the implementation law for ICCPR and ICESCR requires that all government agencies align their laws, regulations, and measures with the two covenants, addressing any inconsistencies within two years of the law’s enactment through legislative amendments or administrative improvements.Footnote 53 This requirement implies that international human rights protections should serve as the prevailing standards. To honour this legislative intent, the two covenants should take precedence over inconsistent domestic legislation, even if such legislation has not yet been amended by the Legislature. Consequently, courts should have the authority to apply the covenants directly to overrule incompatible domestic standards.Footnote 54
Moreover, it is argued that the legal authority of the human rights protections in the two covenants should not rely solely on the implementation law, which is, after all, a domestic law. Instead, their authority should be derived directly from the covenants themselves, which are treaties that Taiwan has adopted as a sovereign state. In this view, treaties inherently hold greater authority than domestic laws, and the international human rights treaties ratified by Taiwan should take precedence over any conflicting domestic law.Footnote 55
B. International human rights treaties vis-à-vis the constitution
The next question to consider is whether international human rights treaties can attain the supreme status of the Constitution. On one end of the spectrum, there is the view that the ICCPR and ICESCR hold the status of domestic laws only. They do not provide a constitutional basis binding on TCC. This position appears to be the conventional approach among Taiwan’s constitutional law jurists, who generally agree that the Constitution – and the Constitution alone – should be the supreme law of the land.Footnote 56
Nevertheless, there is considerable scholarly support for elevating the two covenants and other essential international human rights protections to constitutional status. The arguments made by these scholars highlight their understanding of the connection between international law and the ROC Constitution, especially concerning the state’s obligations (including the obligations of the judicial branch) towards international law.
One perspective is based on the text of the ROC Constitution itself, specifically, Article 141, which mandates that the foreign policy of the ROC shall “respect treaties and the Charter of the United Nations”. The term “respect”, while seemingly modest, is argued to prevent the ROC from violating treaties. These treaties should be viewed as having constitutional authority, thereby binding all branches of the state, including the executive, legislative, and judiciary.Footnote 57 While innovative, this interpretation may be seen as overstated, given that “respect” does not appear to carry the normative force of “compliance”.
An alternative approach does not rest on the Constitution’s wording but instead emphasises the ROC Constitution’s open nature and the global trend of “internationalising constitutional law”. Adopted in 1947, the ROC Constitution reflected the post-war focus on universal human rights. Therefore, this perspective argues that the Constitution should adapt to international norms, and the TCC ought to regard the two human rights covenants and other key treaties as constitutional sources.Footnote 58
Another approach similarly suggests that the Constitution should fulfil Taiwan’s treaty obligations and honour the holistic nature of human rights outlined in the covenants, specifically urging the TCC to use Article 22 of the Constitution, which protects “all other freedoms that are not detrimental to social order or public welfare”, to enforce protections in the ICCPR and ICESCR as an essential component of the Constitution.Footnote 59
At the very least, scholars with varying perspectives seem to agree that certain rights enshrined in international human rights treaties are considered jus cogens, which should not only override domestic laws but also hold constitutional authority,Footnote 60 although different views exist as to what exactly constitutes jus cogens.Footnote 61
Regarding the role of international human rights norms in Taiwan’s legal system, the author takes the view that Taiwan, like other sovereign nations, possesses the inherent right to undertake the sovereign act of accepting human rights obligations as an essential component of the international order. The right of Taiwan in this regard is not undermined by its inability to deposit ratification instruments, a limitation imposed by the political actions of other states and international organisations, which lies beyond Taiwan’s control. Once Taiwan completes all feasible ratification procedures within its powers, these obligations should bind the state as a whole. No actions taken by Taiwan’s executive, legislative, or judicial branches should contradict the state’s international commitments. These obligations arise not from the legislative measures known as implementation laws, but from the sovereign’s commitment to comply with the international order. Should any domestic actions, including legislation, conflict with these international commitments, they should be overridden by the nation’s obligations.
Moreover, these human rights obligations differ significantly from other treaty obligations, such as those related to trade and the economy. They represent the state’s commitment to protect rights within its sovereign powers – a commitment of a constitutional nature. When Taiwan undertakes such obligations of a constitutional nature, its Constitution should concurrently reflect the sovereign’s promise. The author agrees with the view that the mechanism for achieving this lies in Article 22 of the Constitution, which safeguards “all other freedoms that are not detrimental to social order or public welfare”.Footnote 62 This provision’s broad scope is designed to provide a comprehensive rights framework, and the TCC should honour the state’s international human rights commitments through this constitutional provision.
This understanding of international human rights law carries significant implications. Despite impressive progress in human rights protections in Taiwan’s practice,Footnote 63 a gap remains between international human rights norms and Taiwan’s constitutional protections. Taiwan’s Constitution primarily addresses “first-generation” human rights, namely civil and political rights, while marginalising other categories like economic, social, cultural, developmental, and environmental rights. To the extent that economic, social, and cultural rights are mentioned, they are phrased in Chapter 13 of Taiwan’s Constitution in terms of a policy matter,Footnote 64 i.e. “Fundamental National Policies”, rather than rights enjoyed by people as provided for in the UDHR and the ICESCR. For example, Article 11 of the ICESCR – the right of everyone to an adequate standard of living, including adequate food, clothing, and housing, and to the continuous improvement of living conditions – does not easily find a counterpart in Taiwan’s Constitution or the Constitutional Court’s interpretations. A rights-based approach would better enable people to claim their legal entitlements and seek redress against the government, as compared to a policy-based approach.Footnote 65 Systematic incorporation of international human rights norms by the TCC therefore has the potential to reshape domestic jurisprudence, especially in areas beyond civil and political rights.
VI. Conclusion
The relationship between the TCC and international law is complex because the application of international law, including international human rights law, presents a dilemma in Taiwan that courts in other countries do not face. On the one hand, Taiwan has been excluded from the United Nations and many international organisations due to the objection of the PRC, and is therefore unable to be a party to numerous significant international treaties. On the other hand, the TCC has been renowned for its progressive, globally-oriented perspective that embraces universal values since Taiwan’s democratisation. These two contrasting and sometimes conflicting phenomena together shape the Court’s distinctive approach to interpreting and approaching international law.
To understand the patterns and evolution of the TCC’s practice in citing international law in its decisions, this article proposes a typology based on two dimensions – legal effect and impact level. The first dimension distinguishes advisory citations from authoritative citations based on whether international law is considered legally binding. The second dimension categorises citations into reaffirming, formative, and prospective, reflecting their varying levels of impact on the Court’s decision. Historically, the TCC’s use of international law citations had a limited impact on the depth and direction of its rulings. International human rights norms were often treated by the Court as persuasive (advisory citation) and used to reinforce existing constitutional protections (reaffirming citation) or to direct future legislative and administrative reforms (prospective citation). However, in recent years, especially since Taiwan’s adoption of the ICCPR and ICESCR, the TCC’s approach has evolved markedly. Human rights treaties are increasingly influencing the Court’s reasoning to support new rights protections (formative citation), going beyond simply reaffirming established constitutional rights. Moreover, the Court has begun treating international treaties as legally binding (authoritative citation), which indicates a shift towards recognising their obligatory nature.
This article further examines the practical, normative, and strategic dimensions of the Court’s rationale for referencing international law. Specifically, when Taiwan is not a formal party to the treaty, yet the Court still cites such international treaties, considerations may include addressing gaps in the domestic legal framework, boosting the normative legitimacy of its jurisprudence, and signalling both domestically and internationally its commitment to international human rights standards. These considerations, which are not mutually exclusive, suggest the TCC’s sensitivity to, and adaptability in, a globalised legal environment – despite Taiwan’s exclusion from many treaty regimes.
Finally, since Taiwan’s creative adoption of human rights treaties, there has been a growing scholarly interest in the status of these treaties, reflecting an evolving understanding of the role of international human rights norms within Taiwan’s legal and constitutional framework. Innovative arguments have been presented in favour of elevating these treaty protections above domestic laws. Scholars further advocate for these international human rights norms to be recognised as constitutional norms or, at the very least, to be integrated into Taiwan’s constitutional practice in a significant way.
A division has emerged within Taiwan’s academic circles regarding this debate. On one side, some scholars, particularly those from traditional legal backgrounds, maintain a certain aloofness towards international jurisprudence, partly due to Taiwan’s prolonged international isolation. In contrast, another group of scholars actively advocates for international legal norms, viewing them as essential to Taiwan’s commitment to “internationalisation”, “progress”, and deeper “integration into the global community”.Footnote 66 This dichotomy reflects broader discussions within Taiwan, where an ongoing struggle exists to reconcile the jurisprudence of a historically isolated nation with the dynamic demands of global legal practices – a perpetual conundrum that continues to shape Taiwan’s legal landscape.
Acknowledgements
In loving memory of Professor Jerome A. Cohen (1930–2025), whose pioneering spirit, fearless integrity, and boundless compassion and kindness nurtured and continue to inspire generations of scholars, including the author.
Funding statement
None.
Competing interests
The author declares none.
Appendix. Citations of International Norms in Taiwan’s Constitutional Cases (as of December 2023)
Yu-Jie Chen is an Associate Research Professor at the Institutum Iurisprudentiae, Academia Sinica, and a Non-Resident Affiliated Scholar at the U.S.-Asia Law Institute, NYU School of Law.
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