A congressional rebellion has finally delivered a verdict on the war that has consumed the Middle East for nearly four months. On Tuesday, for the first time since the War Powers Resolution was enacted in 1973, both chambers of Congress approved a concurrent resolution directing a president to end a military conflict. The Republican controlled Senate voted 50‑48 in favour of the measure, which had passed the House earlier this month.
Yet, for all its historical weight, the resolution is almost certain to have no practical effect on the war. It does not carry the force of law, it will not be sent to the White House for the president's signature, and the Trump administration has already declared that it will ignore it.
The resolution, known as a concurrent resolution, directs President Trump to "remove United States Armed Forces from hostilities against the Islamic Republic of Iran" unless Congress declares war or authorises the use of military force. It was passed by four Republicans, Sens. Rand Paul, Lisa Murkowski, Susan Collins and Bill Cassidy joining Democrats in the Senate, while four Republicans in the House also crossed party lines.
The vote marked the first time both chambers have approved such a measure, adding to the political pressure on a president who has faced little resistance from his party on matters of war. However, the measure is a concurrent resolution, not a joint resolution. It does not require the president's signature and therefore lacks the force of law. As one legal expert put it, “the executive branch will likely ignore it on constitutional grounds”.
The administration has argued that the resolution is unconstitutional and thus not binding. Secretary of State Marco Rubio and others have pointed to a 1983 Supreme Court ruling that cast doubt on the validity of congressional measures that do not require a president's signature. The White House has also maintained that the conflict had already ended under an April ceasefire ordered by Trump, effectively restarting the 60‑day clock under the War Powers Act.
Legal experts say the question remains contested and is likely to be settled in the courts. But even if a court were to take up the case, it is unclear who would have standing to sue. Scott Anderson of the Brookings Institution noted that “it’s not clear who might have standing to sue to enforce it”, though he expected someone would try. In the meantime, the administration has signalled that it will simply ignore the resolution.
For Congress to genuinely compel an end to the war, it would need to pass a joint resolution, a measure that does require the president's signature and would be subject to a veto. President Trump has made clear that he would veto any binding legislation that restricts his authority. To override a veto, Congress would need a two thirds majority in both chambers, an almost impossible threshold given the slim Republican majorities. Democratic senators have been attempting to force votes on a joint resolution led by Sen. Tim Kaine, which advanced in the Senate last month but has not yet been brought to a final vote. Senate Minority Leader Chuck Schumer has vowed to continue forcing votes, hoping to pick off more Republicans. But even if a joint resolution were to pass, it would face a certain veto and almost certainly fail to be overridden.
Beyond the legislative path, Congress could use its power of the purse. The Pentagon has sought an additional $80 billion to cover the costs of the Iran war. Lawmakers could refuse to appropriate those funds, effectively starving the conflict of resources. However, such a move would be politically fraught and would require the same supermajorities to overcome a veto. The administration could also argue that ongoing ceasefire negotiations and the peace agreement with Iran render the resolution moot, making it even harder for opponents to gain traction.
The passage of the concurrent resolution is a significant political rebuke. It reflects growing unease within the Republican Party about a war that has become deeply unpopular with the American public, as petrol prices have spiked and the conflict has dragged on. It also signals that the president can no longer count on unified support from his own party on matters of war. But the resolution is a statement, not a command.
It will not halt a single airstrike, nor will it force the withdrawal of a single soldier. For now, the negotiations in Switzerland proceed, and the Strait of Hormuz remains a battleground of competing interests.