On June 22, 2025, the United States attacked three nuclear facilities in Iran. This action followed difficult negotiations during the spring of 2025 between the Trump administration and Iranian leaders over Iran’s nuclear program. On June 13, as the progress of these negotiations looked dubious, Israel launched its own preemptive strikes against Iran and its nuclear program. Israel urged the United States to join in the attacks, as the United States possesses “bunker buster bombs” that could damage Iranian facilities located deep underground. After mixed signaling, President Donald J. Trump authorized the June 22 strike. The United States claims that its strike was consistent with international law as lawful collective self-defense of Israel, but this position rests on the tenuous legality of Israel’s own strikes as lawful individual self-defense. Also disputed are the legality of the strike under U.S. domestic law and the scope of the damage caused by the United States. Following the strike, Iran responded several days later with a token attack on U.S. military bases in Qatar. At the time of this writing, a ceasefire of sorts is in place, but the possibility of further hostilities remains high.
For many years, U.S. presidents have sought to prevent Iran from building nuclear weapons. Iran has been a non-nuclear party to the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) since 1970,Footnote 1 but it has not complied with its treaty obligations, is strongly suspected of pursuing nuclear weapons, and has long been watched closely by the International Atomic Energy Agency (IAEA), which is the watchdog for the NPT.Footnote 2 A decade ago, in 2015, the Obama administration worked with other major countries in painstakingly negotiating an arrangement with Iran known as the Joint Comprehensive Plan of Action (JCPOA), which reduced significant sanctions on Iran in exchange for Iran’s curtailment of its nuclear program over a fifteen-year period.Footnote 3 The first Trump administration reneged on this deal, leading Iran to redouble its efforts toward nuclear weapons.Footnote 4 Subsequent efforts by the Biden administration to restore the Obama-era deal were unsuccessful. During the decade between 2015 and 2025, U.S. administrations also sought to reduce or punish Iran’s actions elsewhere in the Middle East, including its support for Hezbollah, Hamas, and the Houthis. Perhaps the most dramatic—and legally contentious—U.S. activity in this regard was an air strike in 2020, authorized by President Trump during his first term in office, that killed Qasem Soleimani, the leader of the Quds Force of Iran’s Islamic Revolutionary Guard Corps, as he was traveling in Iraq.Footnote 5
When President Trump took office for the second time in January 2025, U.S. intelligence reports suggested that Iran could convert its existing enriched uranium into weapon-usable uranium within days.Footnote 6 But these reports also concluded that Iran was at least a year away from being able to maneuver this uranium into a ballistic warhead and that it had not made a final decision to create a nuclear weapon.Footnote 7
In early February, President Trump announced a policy of “maximum pressure” on Iran, stating that “[w]e must deny Iran all paths to a nuclear weapon and end the regime’s nuclear extortion racket.”Footnote 8 He also signaled a wish to negotiate with Iran over its nuclear program, sending a letter to that effect in March to Iran’s supreme leader, Ayatollah Ali Khamenei.Footnote 9 President Trump indicated that the United States would resort to force if negotiations failed.Footnote 10 After some delay and hesitation, Iran agreed to negotiations, which commenced on April 12 and were facilitated by Oman.Footnote 11 Multiple rounds of negotiations in April and May failed to produce an agreement. As June arrived, the outlook for successful negotiations looked bleak.Footnote 12 Separately, on June 12, the IAEA found Iran in non-compliance with its international legal duties due to “many failures to uphold its obligations since 2019 to provide the Agency with full and timely cooperation regarding undeclared nuclear material and activities at multiple undeclared locations in Iran.”Footnote 13
The following day, June 13, Israel launched a series of attacks against Iran aimed at damaging Iran’s nuclear program. Israel had long shown an interest in force over diplomacy regarding this program; it had carried out covert attacks on Iran’s nuclear facilities and nuclear scientists over the years, and it had opposed the JCPOA from before its inception.Footnote 14 Additionally, and reflecting the broader tensions between Israel and Iran, in 2024 Israel twice carried out overt strikes in Iran aimed at damaging its military sites—steps taken following Iranian missile attacks on Israel which in turn had followed the targeted killings by Israel of Iranian officials or allies.Footnote 15 The attacks launched by Israel on June 13, 2025, were apparently long in the making and had been delayed until that date because of the ongoing U.S. negotiations and in the hope of U.S. support.Footnote 16
The Israeli strikes on June 13 and in the days that followed had numerous targets, including Iranian nuclear facilities, Iranian military sites, Iranian military leaders, top Iranian scientists, and an Iranian prison that housed political prisoners.Footnote 17 Significant civilian deaths were reported in addition to military casualties.Footnote 18 Iran responded by launching missiles at Israel. Many of these were intercepted and there were relatively few deaths, but there were numerous buildings that were severely or partially damaged, including residential buildings and a hospital that received a direct hit.Footnote 19
The Trump administration initially emphasized that the United States was not involved in the Israeli attacks. Secretary of State Marco Rubio described Israel’s strikes as “unilateral,” emphasized that the United States is “not involved in strikes against Iran,” and warned Iran against “target[ing] U.S. interests or personnel.”Footnote 20 Over the week that followed June 13, President Trump publicly vacillated on whether the United States would seek further negotiations with the Iranians or instead launch its own strikes.Footnote 21
On June 22, the United States bombed three nuclear facilities in Iran. This attack—called “Operation Midnight Hammer”—involved a combination of stealth bomber planes that had departed eighteen hours earlier from Missouri and missiles launched from 34U.S. submarines.Footnote 22 The stealth bombers dropped “bunker buster bombs” on Fordow and Natanz, two Iranian nuclear enrichment facilities.Footnote 23 Dropped from a great height, these bombs can penetrate deep into the earth before detonating enormous explosives on a delayed fuse.Footnote 24 Therefore, they could potentially reach Fordow, which is deep underground, and the portions of Natanz that are deep underground.Footnote 25 The third nuclear facility, Isfahan, was targeted with submarine-launched missiles focused only on inflicting surface-level damage, reportedly because the site’s considerable depth would have thwarted even bunker buster bombs.Footnote 26
The international legality of the U.S. bombings is sharply contested. As a matter of international law and where, as here, the Security Council has not authorized military intervention, the United States may only use force against another state in lawful individual or collective self-defense.Footnote 27 Article 51 of the UN Charter further provides that “[m]easures taken by [nations] in the exercise of this right of self-defence shall be immediately reported to the Security Council,”Footnote 28 and this is typically done through the submission of a letter to the Council. Immediately following the U.S. attack, and before the United States submitted an Article 51 letter, Iran submitted a letter to the Council that objected to “the unlawful use of force by the United States against the sovereignty and territorial integrity of the Islamic Republic of Iran” and requested that the Council convene an emergency meeting.Footnote 29
At the emergency meeting, held on June 22, the United States stated that its attacks “sought to eliminate a long-standing but rapidly escalating source of global insecurity and to aid our ally Israel in our inherent right of collective self-defence, consistent with the UN Charter.”Footnote 30 Other participants expressed different views regarding the desirability or the legality of the U.S. action (or both). UN Secretary-General António Guterres described the bombing as a “perilous turn.”Footnote 31 Representatives from Algeria, China, Iraq, Pakistan, Russia, and Sierra Leone (as well as Iran) expressed skepticism—or total disbelief—about the legality of the U.S. bombing.Footnote 32 Only Israel offered clear support for the U.S. action, although some states expressed their opposition to Iran’s development of nuclear weapons.Footnote 33
Several days later, on June 27, the United States submitted its Article 51 letter to the Security Council. The letter described the United States as having “exercised the inherent right of collective self-defence and advanced vital [U.S.] interests in eliminating Iran’s nuclear programme.”Footnote 34 The letter noted the context of “more than four decades over which the Islamic Republic of Iran has launched unprovoked attacks against the United States and other [UN] Member States.”Footnote 35 It also discussed Iranian hostility to Israel, including the 2024 missile attacks, and described Israel’s strikes of June 13 as “the latest stage of this international armed conflict” in which “Israel responded to the threat posed by Iran’s nuclear and ballistic missile program[s].”Footnote 36 The letter continued:
In close coordination with the Government of Israel, the United States has taken necessary and proportionate action—directed solely against the Iranian nuclear programme—to defend Israel and also to protect our own security, citizens and interests, consistent with Article 51 of the Charter of the United Nations. The strikes taken on 22 June occurred because peaceful measures were exhausted…. Iran refused to negotiate in good faith or to cease enriching uranium beyond the threshold needed for peaceful, civilian power generation….
The United States remains committed to pursuing a deal with the Iranian government…. But President Trump has also warned that the consequences for any Iranian [military] response will be dire. Accordingly, … [the United States] reserves the right to take such additional actions as may become necessary in its inherent right of self-defence to respond to future attacks or threats of attacks against [U.S.] nationals and [U.S.] personnel and facilities, or in the collective self-defence of its allies and partners.Footnote 37
Since the defense of Israel is the core of the justification offered by the United States for its attack, the legality of its actions depends on whether it can properly invoke collective self-defense on Israel’s behalf. This depends in turn on whether Israel’s attack on Iran’s nuclear facilities constituted a lawful exercise of self-defense.Footnote 38
With respect to perhaps the most similar historic parallel—Israel’s bombing of Iraq’s Osirak nuclear reactor in 1981—the Security Council had unanimously condemned this bombing as a “clear violation” of the UN Charter.Footnote 39 Similar to its explanation for the 1981 attack, Israel justified its June 2025 strikes as responding to “the threat of imminent Iranian attacks,” noting Iran’s public calls for the annihilation of Israel and stating that “[t]his was the last window of opportunity to prevent Iran from acquiring nuclear weapons, and takes place after diplomacy proved ineffective.”Footnote 40 The legal viability of this line of reasoning depends first on concluding that international law authorizes self-defense prior to an imminent armed attack and second on concluding that the traditionally strict criteria for imminence were met in this situation.
Israel’s letter to the Security Council also referenced the 2024 Iranian missile strikes and described Israel as acting amid an “ongoing armed conflict” with Iran.Footnote 41 Some international law experts who agree that Israel is in a pre-existing armed conflict with Iran consider that Israel’s legal right to self-defense follows inherently from the armed conflict, although its strikes would still need to be necessary and proportionate as acts of self-defense.Footnote 42 The time lag since Iran’s last direct strikes on Israel in 2024 and the scale of Israel’s June 2025 strikes raise significant questions about necessity and proportionality under this theory.
President Trump’s authorization for the attack also faced criticism that it violated U.S. domestic law. The U.S. Constitution entrusts the power to “declare [w]ar” to Congress.Footnote 43 The extent to which presidents can unilaterally initiate uses of force that fall short of war is sharply contested, as indeed is the question of what falls short of “war.” Moreover, the War Powers Resolution, enacted in 1973, contains further limits on the president’s power to initiate uses of force, including requiring: prior consultation with Congress (where possible); prompt reports to Congress regarding any new hostilities; and a termination of hostilities within sixty days unless there is specific congressional authorization to continue hostilities.Footnote 44 The War Powers Resolution also provides for special procedures to allow Congress to promptly consider proposed legislation authorizing the hostilities or ordering their immediate cessation.Footnote 45
In a letter to Congress dated June 23 that referenced the reporting obligations of the War Powers Resolution, President Trump justified the strikes as “limited in scope and purpose” and “taken to advance vital United States national interests, and in collective self-defense of our ally, Israel, by eliminating Iran’s nuclear program.”Footnote 46 President Trump asserted that “I acted pursuant to my constitutional authority as Commander in Chief and Chief Executive and pursuant to my constitutional authority to conduct United States foreign relations.”Footnote 47 Notably, President Trump did not claim to be acting under any existing congressional authorization—thus implying that the War Powers Resolution’s sixty-day clock for termination of hostilities in the absence of an authorization would be applicable.Footnote 48 Although the letter is under-theorized, it appears to argue that the strikes did not rise to the level of a “war” for U.S. constitutional purposes and that the president could constitutionally use force to protect U.S. interests. This approach is consistent with the constitutional reasoning of presidential administrations (of both political parties) in recent years,Footnote 49 though it is unclear whether it reflects the proper constitutional scope of unilateral presidential war powers. The letter further stated that “[t]he United States took this necessary and proportionate action consistent with international law, and the United States stands ready to take further action, as necessary and appropriate, to address further threats or attacks.”Footnote 50
Shortly after Israel began its attacks on Iran, a Democratic senator introduced a bill that would have barred U.S. hostilities with Iran (except in defense against an imminent attack or if a specific authorization was subsequently passed).Footnote 51 After the June 22 strike, the Senate took up this bill, pursuant to the War Powers Resolution’s special procedures for speedy consideration. The Senate rejected advancing the bill by an almost entirely party-line vote of 53–47, illustrating the strong control that President Trump has over his party.Footnote 52
In addition to sharp debates about the legality (and wisdom) of the strikes, there has also been considerable disagreement over their effectiveness. In the immediate aftermath of the strikes, President Trump proclaimed that “Iran’s key nuclear enrichment facilities have been completely and totally obliterated.”Footnote 53 Several days later, the White House put out a press release stating that “Iran’s Nuclear Facilities Have Been Obliterated – and Suggestions Otherwise are Fake News.”Footnote 54 (“Take it from those who actually know,” the press release stated, and then offered a long line of quotations beginning with one from President Trump.)Footnote 55 Other sources, however, suggest that the damage was major but not existential, and that Iran could be back to its pre-strike status within months.Footnote 56
In the aftermath of the U.S. strike, Iran retaliated on June 23 with an attack on a U.S. military base in Qatar.Footnote 57 Iran gave Qatar warning of this attack, and all the Iranian missiles were intercepted.Footnote 58 Qatar objected strongly to this “blatant violation of the sovereignty and airspace of … Qatar, international law and the Charter of the United Nations.”Footnote 59 President Trump appeared to recognize this attack as a token response that did not warrant further escalation.Footnote 60 That same evening, he announced that a ceasefire had been reached between Iran and Israel.Footnote 61 After some messiness regarding the timing of its implementation, the ceasefire took effect.Footnote 62
As of the time of this writing, the ceasefire is still in effect. Yet the underlying tensions that provoked the confrontation remain. The Trump administration has expressed its commitment to keeping Iran from getting a nuclear weapon and reiterated its willingness to turn to force if diplomacy fails. For its part, Iran has reiterated that it may withdraw from the NPT, especially if France, Germany, or the United Kingdom use power delegated to them under Security Council Resolution 2231 (the Resolution implementing the JCPOA) to restore the world-wide sanctions that existed against Iran pursuant to pre-JCPOA Security Council resolutions.Footnote 63 And even if the United States and Iran were to reach a negotiated arrangement, it is far from clear what Israel would do. Moreover, these challenges are only a piece of the broader geopolitical tensions between the United States and Iran (and between Israel and Iran). More turmoil and perhaps more armed conflict lie ahead.