The recent U.S. military strike on Iranian nuclear facilities raises an important legal question: Was the strike lawful under international law and U.S. domestic law? The answer is no. The strike does not meet the requirements set by either legal guideline.
Under international law, the use of force is generally prohibited except in cases of self-defense under Article 51 of the U.N. Charter. The U.S. might justify airstrikes on Iran by invoking its own right of self-defense, but a more straightforward legal route would be collective self-defense, supporting Israel at its request. Whether this is lawful depends on whether Israel's campaign itself is a legitimate act of self-defense. Here, the U.S. and Israel adopt broader views than much of the international community. While the International Court of Justice (ICJ) and many states require a specific and imminent armed attack to justify force, the U.S. allows for a broader interpretation, accepting threats based on hostile patterns, proxy actions or long-term threats like Iran’s potential nuclear capability. U.S. strikes rely on a broad view of self-defense, shared by Israel, that includes long-term threats and patterns of hostility. But most of the international community rejects this. Self-defense may apply preventively only if an armed attack is imminent. However, Israel’s right of self-defense (thereby the U.S.’ right to collective self-defense) cannot be justified on this basis, as Iran’s nuclear strike capability was, to public knowledge, neither existent nor imminent.
Even if the strike was allowed under international law, it must still comply with U.S. domestic law. The Constitution gives Congress the power to declare war. While the president is commander-in-chief of the armed forces and can order attacks, his decisions must be within the guidelines of what is authorized by Congress. The president may only use force without congressional approval when responding to an attack or when protecting U.S. persons in immediate danger. There was no attack on the U.S., no threat to U.S. persons, and no emergency that required immediate action. Therefore, the president needed congressional approval before ordering a strike. The president did not seek or receive that approval.
The War Powers Resolution of 1973 requires the president to consult with Congress before introducing U.S. forces into hostilities. News suggests that only Republican members of Congress were informed in advance. That is not meaningful consultation. As a result, the War Powers Resolution was not fully followed. Some may argue that past Authorizations for Use of Military Force (AUMFs) apply. The 2001 AUMF allowed force against those responsible for the Sept. 11 attacks. Iran is not covered by this law. The 2002 AUMF authorized force against Iraq, not Iran. Using these AUMFs to justify a strike on Iran goes beyond their original purpose and legal limits.
The U.S. Supreme Court has set a framework for evaluating presidential power in the case of Youngstown Sheet & Tube Co. vs. Sawyer. When the president acts with Congress’s support, presidential power is at its strongest. When Congress is silent, the president operates in a “twilight zone.” When the president acts against Congress’s will, presidential power is at its lowest.
In this case, members of Congress have introduced a resolution opposing unauthorized force against Iran. If the president's action falls within Youngstown’s "zone of twilight," where congressional intent is unclear, he may rely on Article II powers. Though weaker than express authorization, courts might still uphold such action as lawful. However, if the strike falls into Youngstown’s third category – acting against Congress’s will – the legal basis is much weaker. Even without formal rejection, proposed limits may signal disapproval, making the strike potentially unconstitutional and unlawful under domestic law.
This situation shows why the Constitution gives Congress the power to authorize war. The use of force is a serious decision. It should be made with input from elected representatives. Allowing the president to act alone removes that check. The law is clear. The Constitution, the War Powers Resolution, and the U.N. Charter all require more than what was done before this strike. The strike lacked congressional approval, did not meet emergency standards, and did not follow procedures.
Recently, the Republican-led Senate rejected a Democratic resolution requiring congressional approval for further hostilities against Iran, despite Senator Tim Kaine’s argument that only Congress can declare war. President Donald Trump, meanwhile, signaled openness to renewed bombing, citing concerns over Iran’s uranium enrichment. This shows the urgent need for institutional checks on unilateral military action.
Congress must reassert its constitutional role in authorizing the use of force. It can do so by passing legislation to block unauthorized military action, repealing outdated AUMFs, and using funding powers to limit further strikes. American Courts, too, should be open to reviewing executive actions that lack legal grounding.
