‘Occupation is an ugly word, not one Americans feel comfortable with, but it is a fact’. These words of Paul Bremer, the newly appointed head of the Coalition Provisional Authority in Iraq in May 2003, encapsulate common sentiments at the beginning of the twenty-first century. Military occupation engenders considerable passion and has always done so, even if the general disrepute into which the language and practice of military occupation has fallen is of more recent provenance. The passion is evident in the encounters between occupants and occupied, in the memoirs and histories that flourish in the immediate aftermath of occupation, in the memories of participants who would prefer to forget the experience of occupation, and even in the historical studies devoted to occupations. It is, therefore, not surprising that some occupations at least have generated an enormous literature, most notably those of the Second World War and its aftermath.

What is more surprising is that this has not led to any systematic comparative historical study of military occupation as a distinct phenomenon. Even within the context of multiple occupations by a single occupant, study of national experience predominates. This is true of occupations by Nazi Germany during the Second World War, where comparative analysis has gone further than in any other case. Interestingly, after some initial reflections comparing Allied occupation policies in and after the same war, a national focus has almost entirely dominated attention. Beyond these cases comparative study is extremely rare, though the frequency of occupation in the relations between France and Germany has induced some comparative reflection. The task of beginning to write the history of military occupations in general, however, is still outstanding, despite the call for such a historiographical shift by Philippe Burrin, a noted historian of the occupation of France during the Second World War.

Political scientists engaged in such study are even rarer, there being only two works of any substance, both recent and both having quite specific foci distinct from what would be required of histories of military occupation in general. There are recent legal studies that have focused on international territorial administration and which have a strong comparative and historical dimension but these have separated out international territorial administration from military occupation and reach no further back than the administration of the Free City of Danzig and the Saar by the League of Nations after the First World War.

The United States between Empire and Occupation

American experience of occupation was marked by some of the same factors shaping European experience. From an American point of view the trend, and consequences, was forcefully expressed in 1895 by Henry Cabot Lodge:

The United States contributed one of the most influential theorists and advocates of this trend in the shape of Alfred Thayer Mahan, whose influential text The Influence of Sea Power upon History had been published in 1890. More important still, the United States now had the material resources commensurate with these kinds of ambitions. Indeed, in terms of its share of world manufacturing capacity the United States outranked Britain by the turn of the century and stood as the pre-eminent industrial nation in the world. It is true that the United States was still far from having the military capacity these economic resources could support, though the need to develop them was the point of advocacy by men like Mahan.

The events which demonstrated to contemporaries, both American and European, the new status of the United States was the war with Spain of 1898–9, with its striking victory over the Spanish navy in Manila Bay in May 1898. Although this triumph took place in the Philippines, the initial focus of the dispute between Spain and the United States lay in the Caribbean, specifically Cuba. Cuba had long been of strategic concern to the United States, as well as increasing business interest and the object of intermittent annexationist desires. Prior to the war, however, the United States’ position had been to support Spanish colonial authority, if only as an alternative to possible control by more powerful European powers.

The Long Short War

The conflict which began with the French declaration of war on 19 July 1870 was the culmination of a progressive deterioration in Franco-German relations since the Austro-Prussian War. French neutrality in that war entitled them, so they believed, to some form of compensation, of which one possibility was the acquisition of Luxembourg. That option was excluded by the Treaty of London of 11 May 1867 which provided for collective guarantee of the neutrality of Luxembourg and also ended the prolonged Prussian right of occupation of Luxembourg. One of the reasons the French had to be dissatisfied was that European governments were finding it increasingly difficult to engage in the territorial transactions by which they had adjusted the shifting balance of power. This difficulty was no longer just a residue of the territorial settlement of Vienna, fading as its significance was, but was also a product of the growth of nationalist sentiment that made such transactions less acceptable.

While the precise causes of the war remain disputed, both sides invoked and manipulated national sentiment: Napoleon in order to prop up his increasingly fragile and unpopular regime; Bismarck in order to promote Prussian hegemony within the context of a unified Germany. It was, moreover, less the cause than the conduct of the war and its outcome that determined the nature of the occupation and so shocked contemporaries. The sheer speed and extent of the French defeat was remarkable. At the end of what would seem from the perspective of the protracted European conflicts of the twentieth century to be a short war, the European balance of power had been turned upside down, so it seemed to Disraeli. Yet the relative brevity of the war belied the difficulty in ending it, which in turn prolonged and exacerbated the occupation in the process.

Initially it seemed that the siege of one of the French armies in the fortress of Metz and the crushing defeat of the other main army at Sedan on 1 September 1870, ending with the surrender of over 100,000 men and the captivity of Emperor Napoleon, signified the end of the war. From the time of this great victory Bismarck was looking for a peace treaty to end the war.

Understanding the nature of military occupation, both from the perspective of an observer and from the perspective of a participant, is difficult because military occupation as a political phenomenon displays in acute form a tension that is at the heart of many concepts in political life. It is a phenomenon that is shaped both by the normative features that define it at one level, above all by the idea that the occupant enjoys authority but is not sovereign, and the factual features that establish it, above all by the military force that stands behind government by the occupant. It is a phenomenon that cannot be reduced to one or the other of these two sets of features, as if one were the essence of the phenomenon and the other were contingent. Shorn of the defining qualification of the exercise of authority without the right of sovereignty, government backed by force could as well be an instance of conquest, or even in at least some measure the ordinary condition of government. Without the factual exercise of authority the claim to military occupation too readily looks at best like an entirely spurious claim and at worst like a sinister strategy to deprive opponents of the status of legitimate belligerency, though occupants have often stepped back from that conclusion, as had the British and the Italians towards the end of the long nineteenth century.

The necessity of the relationship between the two in order for the phenomenon of military occupation to be meaningful was implicit, and sometimes fairly explicit, in the arguments of contemporaries, especially when occupation seemed to be slipping, usually by intention, into conquest and the assertion of sovereignty. Bosnia-Herzegovina, Cyprus and Egypt all seemed to be cases where the retention of the claim to sovereignty by the ousted sovereign seemed less and less plausible as the occupant showed no sign of imminent departure, as the occupant's claims took on increasingly normative form and the factual power became more pervasive. That was the inevitable inverse of the dependency of the claim to sovereignty of the legitimate power upon some factual condition, albeit one which is put in danger by the very fact of occupation.

Occupation in the Age of Empire

In the decades between the end of the Franco-German War and the outbreak of the First World War there was no occupation by one European Great Power of the territory of another. The territorial simplification of the European map by the unifications of Italy and Germany may have been destabilising for the European international system in the long run, but they removed zones of instability or weakness which had sucked great powers into occupation in the earlier decades of the century. Occupation now took place on the European periphery, with the decaying Ottoman Empire continuing to provide the occasion for resort to occupation as well as risk of war between the Great Powers. The great Eastern Crisis of 1875–8 drew three powers, Britain, Austria-Hungary and Russia, into strategies of occupation but also saw avoidance of war between them as Bismarck orchestrated a settlement at the conference of Berlin in 1878. Although sometimes compared to the Congress of Vienna, the Conference of Berlin symbolised the intricate network overseen by Bismarck which ‘tided Europe over a period of several critical years without a rupture’. The Concert of Europe, if the name was still warranted, managed to resolve successive crises on Europe's periphery, containing in the process the occupations, but with increasing difficulty.

The wider pressures to which the European system was subjected were bound up with the pursuit of empire and the belief that the world was beginning to consolidate into continental or imperial blocs. Calculations of surface area and population, contrasts of land based and maritime power all fed into such speculations and anxieties. Insofar as empire involved the language of occupation, it mostly did so in a quite different sense from the understanding of occupation embodied in the laws of war codified in this period. Claims to exercise effective authority here did not signify the extent of occupied territory but amounted to a claim to sovereignty, though that was a criterion with which European states felt uncomfortable, preferring to base their claims on less stringent criteria, as became apparent at the Berlin Conference of 1884–5, called to discuss the European powers’ respective claims in Africa.

The Laws of War in the Era of Codification

The codification of the law of military occupation was a minor part of a wider process of the codification of international law that accelerated towards the latter parts of the nineteenth cen-tury. It amounted to a veritable ‘cult of codification’. It was fuelled by the same sentiments that lay behind the codification of continental European domestic legal systems, occasionally inducing some of the reservations encountered in that process, namely that codification would inhibit the natural evolution and progress of customary law. Codification of international law, the idea of which went back at least to the beginning of the nineteenth century, clearly presented problems that codification of domestic law did not. Lack of any central international agency to legislate meant that international law had to be understood either in terms of natural law, as a matter of custom and usage, or treaty based law, with the latter being especially difficult to achieve in the highly sensitive area of the laws of war. Only treaty based law brought with it the promise, but not the reality, of the coherence and comprehensiveness that were seen as some of the virtues of domestic codification.

In the case of international law the process was complicated by other factors, some of which facilitated the difficult process of reaching agreement and some of which did not. The process was not helped by the fact that international law as a distinct body of law with dedicated textbooks, institutionalised in European universities, barely existed in the first half of the nineteenth century. Furthermore while in contrast to the general stage of development some elements of international law and the laws of war were relatively well developed, most notably maritime law and the law of prizes in warfare, the very concept of military occupation was recent, inchoate and still frequently entangled in the language of conquest. Ironically, it was helped by some of the very limitations of international law. This law was restricted in scope in the sense that it was seen as regulating a limited number of states, primarily European states.

The Provisionality of the Revolutionary and Napoleonic Order

The wars that would make military occupation a recurrent feature of the European experience for over two decades and that overturned the eighteenth-century balance of power were so often justified in terms of competing principles and constitutional orders that principle and competition of constitutions have been seen as the cause of the wars and the factor behind their continuation. From the Declaration of Pillnitz of 27 August 1791, in which Frederick William II of Prussia and Leopold II of Austria declared ‘that they regard the present position of His Majesty the King of France as a matter of common concern to all the sovereigns of Europe’, and the inflammatory speech of Jacques-Pierre Brissot de Warville, of 20 October 1791, invoking the spectre of an anti-revolutionary conspiracy to be met by war, it readily appeared that the eventual declaration of war against Austria by the French Legislative Assembly on 20 April 1792 was an inevitability. By the same token Napoleon has been seen as the heir of the Revolution, or even as a ‘Robespierre on horseback’, whose opponents finally set the seal on the Revolution at the Congress of Vienna, some of them at least creating a Holy Alliance to smother any revolutionary sparks that might ignite a renewed conflagration.

Others have seen more traditional factors of great power rivalry at work, with the French revolutionaries and Napoleon inheriting the goals of the French monarchy, and France's opponents, and sometime allies, continuing their respective traditions. From this perspective the wars amounted not to the violent imposition of the Revolution but its betrayal and both sides were ultimately corrupted by their attempt to deal with the other. As Albert Sorel put it: ‘In order to deal with the French Revolution, old Europe abdicated its principle: in order to deal with the old Europe the French Revolution falsified its own’. More nuanced accounts have tried to integrate both sets of factors, adding the influence of mutual misperception and miscalculation.

Revolutionary ideology and counter-ideologies of the most diverse kind as well as considerations of power, national or dynastic honour, and misperception and miscalculation continued to feed the wars after 1792.

Occupation and the Concert of Europe

Just as the turmoil of the Revolutionary and Napoleonic Wars had set the framework for the emergence of the concept of military occupation, so too the European settlement embodied in the Vienna Conference and the arrangements for its perpetuation set the framework for the development of the concept and practice of military occupation in Europe and to some extent beyond it. The Vienna Conference and associated alliance system not only provided for a specific territorial settlement which the negotiators intended should endure but also committed the Great Powers, as they were now recognised, to the management of that settlement through the periodic coordination of those Great Powers. Initially that promise of coordination had been tied up with a commitment to the defeat of France, in the Treaty of Chaumont of March 1814. The later Quadruple Alliance of 20 November 1815 reaffirmed their will to oppose the ‘Revolutionary Principles which upheld the last criminal usurpation’, namely the 100 days of Napoleon Bonaparte, and ‘might again, under other forms, convulse France’. Yet France had regained admission to the club of the Great Powers during the Conference at Vienna, membership that was explicitly reaffirmed after Napoleon's final defeat at the time that the Allies agreed upon the early termination of the occupation of French territory, at the Conference of Aix-la-Chapelle in 1818. A British memorandum, invoking and summarising these various agreements concluded that they ‘may be considered as the great Charte, by which the Territorial System of Europe, unhinged by the events of war and Revolution, has been again restored to order’.

While far from entailing any principled renunciation of conquest, as the revolutionary principles of the French once had, the practical effect of these arrangements was to create a considerable predisposition against territorial change and especially territorial change by conquest entailing an immediate displacement of sovereignty. The consequence was that whereas before 1815 it was fundamental disagreement about the territorial settlement of Europe that shaped the emergence of the concept and practice of occupation, after 1815 it was the, albeit fragile, agreement about the territorial settlement that provided the framework for occupation.

Occupation, Conquest and the Constitution of the United States of America

Although the American experience of occupation and conquest was similar enough to that of the Europeans for the Americans to invoke European experiences in order to make sense of their own, the peculiarities of the United States of America stand out in any account of those military occupations. One of the most obvious of these, both to the Americans themselves and to contemporary Europeans, was the US constitution. In matters of conquest, occupation and civil war, the ‘very peculiar constitution of this Government’, as Justice Grier put it in the Prize Cases, played a key role. Justice Grier had in mind the bifurcated allegiance of Americans to both the federal government and the individual state of which they were a member, the respective claims of which were then being tested by civil war. The constitution had also shaped how Americans responded to the possibility and then the increasing reality of territorial expansion. At the outset of the process of expansion, with the Louisiana Purchase of massive tracts from France in 1803, Thomas Jefferson had expressed concern that there was no constitutional provision for the impending ratification of the Louisiana Purchase: the ‘general government has no powers but such as the constitution has given it: and it has not given it a power of holding foreign territory, & still less of incorporating it into a Union’. Jefferson was none the less determined to make the purchase and to ‘rely on the nation to sanction an act done for its great good, without its previous authority’. Jefferson's determination upon conquest would later receive the principled sanction of the Supreme Court, holding that the ‘Constitution confers absolutely on the government of the Union, the powers of making war, and of making treaties: consequently, that government possesses the power of acquiring territory, either by conquest or by treaty’. The court promptly added: ‘The usage of the world is, if a nation be not entirely subdued, to consider the holding of conquered territory as a mere military occupation, until its fate shall be determined at the treaty of peace.’ Its concern though was not with occupied territory but with the precise status and form of government of ceded territory.