Senate Advances Resolution to Force Trump End Iran War Without Congress Approval

The U.S. Senate narrowly voted 50–47 on Tuesday to advance a resolution that would force President Donald Trump to end the war in Iran or secure explicit authorization from Congress, in the first successful move of its kind since the conflict began nearly three months ago nbcnews +1. Four Republicans joined Democrats in the procedural vote, exposing growing unease inside the president’s own party over an open‑ended campaign that has killed at least 14 U.S. troops and cost an estimated $29 billion so far ms.
The measure, authored by Sen. Tim Kaine of Virginia, invokes the 1973 War Powers Resolution to direct Trump to withdraw U.S. forces from “hostilities within or against Iran” unless lawmakers pass a declaration of war or a specific authorization for the use of military force nbcnews +1. The vote came about 80 days after U.S. and Israeli strikes on Iran began on Feb. 28 in “Operation Epic Fury,” a joint air campaign the White House said was aimed at dismantling Tehran’s nuclear and missile capabilities thehill +1.
A Rare Republican Split and a Procedural Breakthrough
The resolution advanced only after Sen. Bill Cassidy of Louisiana, who lost his Republican primary over the weekend, flipped his position and sided with Sens. Rand Paul, Susan Collins and Lisa Murkowski to support moving it to the floor cnbc +1. Three GOP senators were absent; if they had voted no, the motion would have deadlocked and failed washingtonpost.
Cassidy said he backed the measure to force a fuller explanation of the mission, arguing that “the White House and Pentagon have left Congress in the dark on Operation Epic Fury” and that without clarity “no congressional authorization or extension can be justified” ms. Senate Democratic leader Chuck Schumer framed the vote as a turning point, saying Republicans’ “wall of silence on Trump’s illegal war” was beginning to crack after weeks of escalating strikes and shifting war aims cnbc.
War Powers, Executive Authority and Long Odds Ahead
Under the War Powers Resolution, presidents may deploy forces into hostilities for 60 days without prior congressional approval, followed by a 30‑day withdrawal period; Trump has argued that a declared ceasefire around May 1 “terminated” hostilities and reset the clock, a claim many lawmakers dispute nbcnews +1. Legal experts and critics in Congress say the continuing U.S. role — including airstrikes and naval operations around the Strait of Hormuz — amounts to an ongoing war that requires a clear mandate from Capitol Hill wpr +1.
Even if the Senate ultimately passes Kaine’s resolution, it must clear a Republican‑led House that rejected a similar measure in early March, then survive an almost certain veto from Trump, who insists his actions fall squarely within his commander‑in‑chief powers to defend U.S. interests breakingdefense +1. Overriding a veto would require two‑thirds majorities in both chambers, a threshold neither party appears close to meeting nbcnews.
The Bigger Picture
The vote underscored both Congress’s mounting frustration with being sidelined on decisions of war and peace and the structural limits of the War Powers Act in restraining determined presidents. While the resolution may never become law, it forced rare bipartisan defections, put a precise price tag and casualty count on the Iran campaign in public debate, and signaled that Trump’s latitude on further escalation — including threatened strikes on Iranian infrastructure — may face sharper political resistance if the conflict drags on ms +1.
Sources
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US Senate advances measure curbing Trump's Iran war powers Item 1 of 2 A view of the dome of the U.S. Capitol building in Washington, D.C. U.S., September 19, 2025. REUTERS/Kent Nishimura/File Photo [1/2]A view of the dome of the U.S. Capitol building in Washington, D.C. U.S., September 19, 2025. REUTERS/Kent Nishimura/File Photo Purchase Licensing Rights, opens new tab * Summary * Companies * Vote nearly along party lines, 80 days after air strikes began * Measure is several steps from ...
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