The U.S. Launched Joint Military Strikes With Israel on Iran. Does That Require Separate Congressional Approval?

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Air raid sirens wailed across Israeli cities at 8:15 a.m. On February 28, 2026, as the United States and Israel launched coordinated military strikes against Iranian targets. Israeli Defense Minister Israel Katz called it a “preemptive attack” to “remove threats to the State of Israel.” Israel declared a nationwide state of emergency, closed its airspace, and moved its hospitals underground.

The operation raised a legal question that existing constitutional precedent and congressional laws have never clearly answered. When the United States military joins forces with a foreign ally to conduct offensive military operations, does that joint action require separate or additional congressional authorization? Or does it require only what a unilateral U.S. Strike would demand?

The debate over whether a president can order unilateral military strikes without congressional approval is old and at least comprehensible. The president acts, Congress complains, the courts decline to intervene, and everyone moves on. But a coordinated joint operation with a close ally sits in genuinely uncharted legal territory. Constitutional law, the War Powers Resolution of 1973, and prior opinions from government lawyers have never fully addressed that gray zone. Those strikes brought that uncharted territory into the open.

The Structural Problem With Joint Operations

In a unilateral strike, the president of the United States makes an independent judgment of threat and necessity, directs U.S. Military forces, and bears responsibility for the consequences. The legal debate centers on whether the president’s authority exists and whether it was correctly used. Who gave the order and who carried it out is clear: the U.S. President decided, the U.S. Military executed.

In a joint operation, that clarity fractures.

Should Israel have started the strikes and the U.S. Joined as a supporting partner, providing aerial refueling, supplies, and intelligence, or coordinated firepower, the question becomes: did the U.S. President independently decide that the threat warranted U.S. Military participation? Or did Washington simply follow Israel’s decision to strike, treating Israel’s threat assessment as sufficient justification for U.S. Involvement? The second scenario means the U.S. Effectively handed over some portion of war-making authority to a foreign government. Even a close ally does not substitute for an independent U.S. Decision. That is a different constitutional position entirely.

The War Powers Resolution’s text offers no guidance on this scenario. The law requires the president to notify Congress when U.S. Armed forces are “introduced into hostilities or into situations where imminent involvement in hostilities is clearly indicated by the circumstances.” It does not say what happens if those forces are brought in as part of a coordinated action with a foreign ally.

It also does not say whether the notification must spell out the roles of different partners. Nor does it say whether the legal clock starts at a different moment depending on whether the U.S. Is a primary initiator or a secondary participant.

Elizabeth Goitein, senior director at the Brennan Center for Justice and an expert on war powers, has argued that the statute was written when joint operations were far less common and does not contemplate a president joining an ally’s operation rather than independently introducing U.S. forces into hostilities.

No federal court has ever ruled on this question. No previous Congress has successfully forced a settlement of it. The Office of Legal Counsel has not publicly issued an opinion examining how the Constitution’s war-powers provisions apply to joint military operations with foreign allies.

(For background on why courts consistently sidestep these disputes, see our earlier analysis of congressional remedies for unauthorized military action.)

Whose Threat Assessment Counts?

The administration’s notification letter cited “the President’s constitutional authority as Commander in Chief and Chief Executive” and international law as the legal justification for the February 28 strikes. The legal principle of striking first to stop an imminent attack — sometimes called anticipatory self-defense — is recognized in international law and in U.S. Constitutional doctrine.

Netanyahu and other officials framed the strikes in terms of existential and future danger rather than an imminent attack. Netanyahu said in a video statement that Israel and the United States had launched strikes “to remove the existential threat” posed by what he called “the terror regime in Iran.” He added that “for 47 years, the Ayatollah regime has called out ‘Death to Israel’ and ‘Death to America.'” Trump made similar statements on Truth Social: “Our objective is to defend the American people by eliminating imminent threats from the Iranian regime.”

But here is the legal problem hidden in that framing. The U.S. Constitution and international law both require an independent finding of threat by the country claiming the right to use force. When the U.S. Asserts that it acted in self-defense against Iran, U.S. Officials must make an independent assessment. That assessment must find that the threat to the United States, or to U.S. Personnel or interests, is imminent and necessitates an armed response. That judgment cannot simply be borrowed from an ally, even a close one.

Should Israel assert an imminent threat to its civilians from Iran, that may be sufficient to justify Israeli use of force under international law and Israeli constitutional law. But when the U.S. Joins Israel’s strike based on Israel’s threat assessment, without making its own independent finding of threat to the United States, the U.S. Argument for self-defense becomes legally weaker. Washington would be leaning on another nation’s judgment rather than its own. That looks more like defending an ally than defending yourself.

Why Existing Security Agreements Cannot Substitute for Congressional Authorization

The United States and Israel have signed multiple two-sided defense cooperation agreements over the past 70 years. The key agreement is the Mutual Defense Assistance Agreement signed in 1956, which established a framework for U.S. Military aid and defense cooperation.

More recently, in January 2026, weeks before the February 28 strikes, the U.S. And Israel jointly announced a strategic partnership on artificial intelligence research and critical technologies, pledging enhanced defense collaboration.

These agreements are deep and significant. But the key legal question is whether they count as prior congressional authorization for joint military operations. Alternatively, they may only set up a framework for cooperation that does not extend to authorization for kinetic military action.

No U.S.-Israel mutual defense treaty has ever been submitted to the Senate for ratification. The legal relationships are instead contained in executive agreements. These do not carry the force of a treaty and were never voted on by the Senate, which is required to ratify treaties.

The administration might argue that by repeatedly setting aside funds for U.S.-Israel military cooperation, Congress has quietly approved the kind of close military cooperation that led to the February 28 strikes. But that argument assumes a level of congressional intent that may not exist. Setting aside funds for military aid is not the same as authorizing a specific joint military operation. “Budget votes are about resources, not about war-making authority, and ‘appropriations’ is the formal word for those budget votes,” said Oona Hathaway, professor of international law at Yale Law School. That reasoning would effectively allow Congress’s budgeting decisions to be read as authorization for military action — a backward way of deciding who gets to start a war. Congress votes on budgets all the time, often without any expectation that a line item will later be cited as authorization for a war.

Sources: Congressional Research Service analysis of the War Powers Resolution; 2001 AUMF legislative history; Brookings Institution analysis of the 2002 Iraq AUMF.

Can the 2001 or 2002 AUMFs Be Stretched This Far?

From the start of the Trump administration’s escalating rhetoric toward Iran in early 2026, observers wondered whether the administration would cite existing authorizations for the use of military force as justification for strikes on Iran. Specifically, they wondered about the 2001 AUMF or the 2002 Iraq AUMF.

The 2001 AUMF authorizes the president to use “all necessary and appropriate force” against “those nations, organizations, or persons he determines planned, authorized, committed or aided the terrorist attacks that occurred on September 11, 2001, or harbored such organizations or persons.” The statute contains no geographic limit and no expiration date.

Could it plausibly be stretched to cover strikes on Iran? The administration would likely argue that Iran has harbored terrorist organizations, including Hamas, Hezbollah, and the Houthis. It would also argue that Iranian military personnel have coordinated with non-state actors who pose threats to U.S. Personnel.

But Iran is a nation-state, not a terrorist organization. Applying the AUMF to strikes on an entire nation-state would represent an unusual expansion of what the law was meant to cover.

The 2002 Iraq AUMF presents a different problem. The Trump administration cited it in January 2020 as one justification for the strike that killed Iranian military commander Qassem Soleimani. The argument was that Soleimani’s activities in Iraq justified his targeting under the statute. That argument was disputed even when used to justify killing an Iranian official on Iraqi soil. Using it to justify strikes on Iran itself, conducted jointly with Israel, would stretch the legal argument even further. The law is explicitly about Iraq. It would require arguing that any Iranian activity affecting Iraq is within the scope of authorized force. That is an argument that gets weaker the further you stretch it.

Congress, sensing the administration’s potential reliance on AUMF authority, moved to tighten the laws. In February 2026, days before the strikes, House Democratic leaders said they would force a vote on a resolution requiring President Trump to make the case to Congress before using military force against Iran. They emphasized that “any such action would be unconstitutional without consultation with and authorization from Congress.”

The Notification Clock Problem

The War Powers Resolution requires the president to notify Congress within 48 hours of introducing U.S. Armed forces into hostilities. But when exactly does the clock start ticking in a joint operation?

Should Israel strike first and the U.S. Join hours later, does the 48-hour clock start when U.S. Forces first engage, or back-dated to when the joint operation was planned? Simultaneous, coordinated timing might change that analysis entirely. And what about logistical support, intelligence sharing, or mid-flight refueling? Does providing those capabilities, rather than direct strike capability, count as introducing U.S. Forces into “hostilities” at all?

“The notification requirement assumes a clear moment when the U.S. President makes a decision and U.S. Forces cross a threshold,” said Ryan Goodman, editor of Security and a professor at NYU Law who specializes in war powers. “In a joint operation, that moment becomes ambiguous. Are U.S. Logistics personnel part of the strike? Are intelligence analysts? The statute’s language suggests the answer depends on whether they are ‘introduced into hostilities,’ which itself is contestable.”

The real-world consequence is significant. The 60-day clock for continuing military action without congressional authorization begins when the 48-hour notification obligation is triggered. If the administration reads the trigger narrowly, waiting until actual U.S. Combat strikes begin, or even narrowing the definition of what counts as “hostilities,” the clock may start later.

This gives the administration more time to act without congressional authorization. The White House released a letter notifying Congress of the Iran strikes, but the law’s wording gives the administration significant room to choose a favorable interpretation of when the clock started.

How Congress Is Responding, and Why It May Not Matter

The congressional response to the strikes shows the political and legal fault lines on the question of joint-operation authorization.

House Democratic leaders immediately called for a War Powers Resolution vote, saying in a joint statement: “The Iranian regime is brutal and destabilizing, seen most recently in the killing of thousands of protestors. However, undertaking a war of choice in the Middle East, without a full understanding of all the attendant risks to our servicemembers and to escalation, is reckless.” House Foreign Affairs Committee ranking member Gregory Meeks (D-N.Y.), along with House Armed Services Committee ranking member Adam Smith (D-Wash.) and Intelligence Committee ranking member Jim Himes (D-Conn.), released a statement urging the administration to continue diplomatic efforts rather than pursue military action.

Senate Democrats were more divided. Senate Minority Leader Chuck Schumer (D-N.Y.), while expressing concern, did not openly call for enforcement of the War Powers Resolution. Instead, he urged the administration “to consult with Congress and explain to the American people the objectives and exactly why he is risking more American lives.” That framing, urging consultation rather than demanding authorization, pointed to a softer challenge than House Democrats offered.

Republicans largely closed ranks behind the administration. There were exceptions. Rep. Thomas Massie (R-Ky.) co-sponsored a War Powers Resolution with Rep. Ro Khanna (D-Calif.) calling for the removal of U.S. Forces from Iran absent congressional authorization. Senators Tim Kaine (D-Va.) and Rand Paul (R-Ky.) introduced a Senate version of the resolution.

History suggests Congress will not successfully force a resolution. Presidents have rarely been forced to remove troops or stop operations under the War Powers Resolution. Partisan polarization makes bipartisan enforcement even less likely today.

Still, the joint-operation angle has introduced a new element into the debate. Some members argue that Israel’s participation makes the authorization question more urgent, not less. Giving up some measure of military decision-making to a foreign ally could be seen as a more serious constitutional violation than a unilateral presidential decision to strike.

The International Law Dimension: Prevention vs. Preemption

Beyond the constitutional question lies a related question about compliance with international law, particularly the UN Charter’s prohibition on the use of force except in self-defense or with Security Council authorization.

Article 51 of the UN Charter permits individual or collective self-defense “if an armed attack occurs.” Read strictly, that covers only reactive self-defense after an attack has happened. The U.S. Position, stated by various administrations, is that anticipatory self-defense is permissible if an attack is imminent and the necessity and proportionality of the response are met. But international opinion is divided. Many non-aligned nations and prominent international law scholars take a narrower view.

Here is where the legal terms matter. A “preemptive” strike targets an imminent attack. A “preventive” war is fought to stop a state from developing dangerous capabilities at some future point. Preventive wars are generally seen as violations of the UN Charter. Preemptive strikes are more defensible, though still controversial.

A joint U.S.-Israeli strike against Iran based on assessments of Iranian nuclear weapons development and ballistic missile programs falls uncomfortably close to the preventive end of that spectrum. Iran had not imminently attacked the U.S. Or Israel. The threat was characterized as one that might materialize if Iran’s nuclear program continued to develop.

“The U.S. And Israel will argue this is preemptive self-defense based on Iran’s demonstrated intent and capability,” said Michael Schmitt, a distinguished scholar at West Point and a leading authority on international law and the use of force. “Many countries will argue it looks more like prevention, which is not permitted under the Charter.”

The UN Security Council could in theory pass a resolution condemning the strikes. But Russia and China, both permanent members with veto power, would be unlikely to support such a resolution. The strikes will therefore sit in an unclear space in international law. They are potentially defensible under some broad interpretations of anticipatory self-defense, but difficult to defend under more restrictive readings of the UN Charter.

The International Court of Justice has never ruled on the legality of such preemptive joint strikes. It is unlikely to do so soon, as states must bring cases on their own. For a closer look at how the U.S.-Israel-Iran relationship arrived at this moment, see our earlier history of the U.S.-Israel-Iran triangle.

If Iran Retaliates, the Legal Framework Shifts

Iranian retaliation, if it occurs, would change the legal picture in ways that work against the critics of the strikes. A direct Iranian attack on U.S. Military installations or personnel would count as an armed attack on the United States. That would trigger the president’s constitutional self-defense authority under Article II. It would also greatly strengthen the administration’s argument that U.S. Participation in military action against Iran is constitutionally justified.

Israel declared a 48-hour state of emergency on February 28, citing the expectation of Iranian retaliation. U.S. Central Command stated it was prepared for Iranian responses.

Retaliation would also deepen the legal gray zone in a different direction. Should Iran strike U.S. Bases in response to the February 28 operation, would the U.S. Then be allowed to conduct additional strikes on Iran without new congressional authorization? That would lean on the Article II self-defense right triggered by Iran’s retaliation. Or does the War Powers Resolution’s 60-day clock, started by the initial strikes, impose a hard limit on what the U.S. Can do?

The administration would likely argue that a new Iranian attack creates a new right of self-defense, allowing a U.S. Response unconstrained by the WPR clock that started on February 28. That argument is clever but legally questionable. The WPR’s 60-day limitation applies to continued hostilities. If hostilities with Iran are ongoing, the clock should apply to all of them, not just the first strike.

The political reality, though, is that if Iran retaliates and kills American service members, Congress is unlikely to try to limit the administration’s response. It may well feel pushed to grant the administration broad authority to respond.

That would make the abstract constitutional question moot from a practical standpoint. That is how war powers disputes have historically settled themselves: not through legal clarity, but through political facts on the ground.

The Question This Crisis Leaves Open

The February 28 strikes have revealed a genuine gap in U.S. Constitutional law: the absence of clear rules governing joint military operations with foreign allies. The War Powers Resolution contemplates presidential action and congressional response. But it does not address what happens when a foreign ally initiates or co-initiates military action and the U.S. Chooses to participate.

The problem of shared responsibility remains unaddressed by law or precedent. In joint command structures, decisions about what to strike may be made jointly or handed off to whichever partner has better intelligence on a particular objective, and the rules governing when and how to use force must be coordinated.

If the operation breaks the laws of war, which country is legally responsible? And which country’s courts or laws would handle any consequences? These are not hypothetical questions. They come up in every joint military operation.

What may develop instead of legal clarity is a set of informal examples that future presidents will point to. If the February 28 strikes achieve their stated objectives without major escalation, the administration’s legal position may be quietly accepted. It may not be openly endorsed by Congress, but it would go unchallenged. If the strikes fail to achieve objectives or trigger a major retaliation, Congress may demand after-the-fact authorization or try to enforce the War Powers Resolution’s 60-day limit.

The specific test to watch is the 60-day clock. Under the War Powers Resolution, if the administration’s notification letter was filed on or around February 28, the clock for continued military action without congressional authorization expires around late April 2026. Whether Congress tries to enforce that deadline, and whether the administration acknowledges it, will tell us more about the real state of war powers law than any legal opinion the Justice Department’s Office of Legal Counsel might eventually release. The joint-operation question itself will likely remain unresolved until Congress or the courts are forced to face it more directly — and so far, neither institution has shown much appetite for that confrontation.

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