WASHINGTON — The U.S. Senate cast a historic vote Tuesday, backing legislation that would order President Donald Trump to bring American military action against Iran to a stop — the latest sign that some members of his own party are growing increasingly uncomfortable with his leadership.
Senators approved the war powers resolution by a 50-48 margin. The measure had already cleared the House of Representatives earlier this month, driven by rising unease — even within Trump’s own Republican Party — over a conflict that began on February 28 and has grown deeply unpopular.
This marks the first occasion in American history that both chambers of Congress have simultaneously passed a resolution ordering a president to pull U.S. forces out of an active conflict since the War Powers Resolution — more widely known as the War Powers Act — became law back in 1973.
Though the resolution is widely expected to be largely symbolic in its effect, it still represents a notable blow to Trump, who had until recently enjoyed nearly unanimous backing from Republican lawmakers on Capitol Hill.
The vote also comes at a particularly sensitive moment, as the administration is expected to soon ask Congress to approve tens of billions of dollars in funding to cover the costs of the war.
Republicans currently hold narrow majorities in both the Senate and the House, but a handful have begun breaking ranks with the president on select issues as November’s mid-term elections approach — elections that will decide whether the GOP keeps control of Congress.
Some Republicans have already pushed back on other Trump priorities, including his $1.8 billion “antiweaponization” fund intended to compensate political allies he claims were targeted by federal authorities, and they have also stalled a $70 billion bill aimed at funding his immigration enforcement efforts.
A Reuters/Ipsos poll released the same day as the Senate vote found that only one in four Americans feel the war with Iran has been worth the price, and that most Americans are skeptical a ceasefire with Tehran will hold over time.
The Senate tally broke largely along party lines. Four Republicans crossed the aisle to vote with Democrats in favor of the resolution, while all but one Democrat voted yes. Two Republican senators were absent and did not cast votes.
Legal Questions Remain Unresolved
The Trump administration is currently engaged in efforts to negotiate a peace agreement with Iran. Congressional support for the resolution is expected to increase pressure on Trump not to restart military operations — something he has hinted he may do if peace talks break down.
Under the terms of the 1973 War Powers Act, a concurrent resolution passed by both chambers does not require the president’s signature. Congress designed such resolutions as a tool to end military engagements without needing White House approval.
However, legal experts caution that the matter is far from settled. No war powers resolution had ever previously passed both chambers, and a Supreme Court ruling from 1983 stated that such a measure must be sent to the president for signature or veto in order to carry legal weight.
The White House has taken the position that the War Powers Act itself is unconstitutional and therefore not binding on the executive branch.
A White House official said Tuesday that the Senate vote carries no real significance, arguing that because the resolution does not go to the president, it has no force of law — and pointing out that the measure only passed because two Republican senators were not present to vote.
The official also argued that the resolution is moot because U.S. forces were already removed from hostilities when a ceasefire took effect on April 7.
Experts believe the constitutional questions surrounding the War Powers Act will ultimately need to be resolved by the courts.
Scott Anderson, a senior fellow at the Brookings Institution and senior editor of the legal publication Lawfare, offered this assessment: “The executive branch will likely ignore it on constitutional grounds, and it’s not clear who might have standing to sue to enforce it.”
Representative Gregory Meeks of New York, who introduced the resolution in the House, said he considers the measure legally binding and pledged to pursue every available legal avenue to compel the administration to comply with it.
Democrats also pointed to the U.S. Constitution’s language giving Congress — not the president — the authority to take the nation to war. “Congress has to own this responsibility,” said Democratic Senator Tim Kaine of Virginia in remarks on the Senate floor urging his colleagues to support the measure.
A Small But Meaningful Coalition
The resolution had also cleared the House with limited Republican support, passing 215-208 with four Republicans and all Democrats voting in favor.
The four Republican senators who voted for the measure were Susan Collins of Maine, Rand Paul of Kentucky, Bill Cassidy of Louisiana, and Lisa Murkowski of Alaska. Democratic Senator John Fetterman of Pennsylvania was the lone Democrat to vote against it.
Republicans Mitch McConnell of Kentucky and David McCormick of Pennsylvania were absent and did not vote.
Democratic lawmakers have pledged to bring additional war powers measures to the floor, saying they intend to keep forcing Republicans to take public positions on the conflict.
Separately, under a 2015 law passed when then-President Barack Obama was negotiating a nuclear deal with Iran and other world powers, Congress retains the right to review and vote on any peace agreement with Tehran that touches on Iran’s nuclear program.
Senate Republican Majority Leader John Thune of South Dakota said Tuesday that he anticipates Congress will indeed review and vote on whatever peace deal is eventually reached with Iran.
