The Senate on Tuesday approved a resolution directing President Donald Trump to end the military conflict in Iran or seek congressional authorization to continue it, marking a rare bipartisan challenge to the president’s war powers. The vote passed narrowly, 50 to 48, with four Republicans joining Democrats in support of the measure.

The resolution serves as a formal rebuke of the ongoing conflict, which entered its sixth month after a series of hostilities beginning in late February. Although the resolution lacks the force of law and cannot compel a policy change, it underscores growing unease in Congress—particularly among some Republicans—over the administration’s handling of the situation and its decision to continue military operations without explicit congressional approval.

This vote is notable as the first time since the War Powers Resolution of 1973 that both chambers of Congress have passed a concurrent resolution instructing the president to end a conflict. The House of Representatives approved the measure earlier this month, despite opposition from some Republican leaders. On Tuesday, Senator John Fetterman of Pennsylvania was the only Democrat to vote against the resolution, while Republicans Rand Paul, Lisa Murkowski, Susan Collins, and Bill Cassidy broke ranks to support it. The absence of prominent Republicans, including Senate Minority Leader Mitch McConnell due to health reasons, also contributed to the resolution's narrow success.

The War Powers Resolution, originally enacted following conflict over the Vietnam War, aims to reassert congressional authority over decisions to engage in or extend hostilities. Advocates of Tuesday’s measure contend that the Constitution grants Congress the sole power to declare war, a principle Senator Tim Kaine of Virginia emphasized ahead of the vote. However, some lawmakers, including Republican Foreign Relations Committee Chairman Jim Risch, questioned the resolution’s practical impact, citing legal uncertainties and suggesting President Trump was unlikely to adhere to its directive.

Despite a cease-fire and ongoing diplomatic negotiations, approximately 50,000 U.S. troops remain deployed in the Middle East, including forces aboard naval vessels and thousands of Marines. The Trump administration is expected to request billions of dollars in additional funding related to the conflict as early as Wednesday.

Tensions persist over the prospects for a long-term settlement, with contradictory statements emerging about Iran’s willingness to allow extensive nuclear inspections. President Trump claimed Iran had agreed to “the highest level Nuclear inspections,” a development welcomed by some pro-military lawmakers, though Iranian officials denied any such agreement had been reached during recent talks in Switzerland. Trump indicated that U.S. forces might maintain a presence to rapidly reinstate a military blockade of the Strait of Hormuz if necessary.

The conflict’s political implications have heightened as Republican lawmakers grapple with constituent dissatisfaction and worry about the broader economic and regional security risks. Democrats hailed the Senate vote as a crucial step toward reining in unilateral presidential war-making and addressing what they characterize as a costly and poorly defined conflict. Some Republicans opposed the resolution on the grounds that the current cease-fire, along with ongoing negotiations, rendered the measure premature.

Meanwhile, Trump recently signed a memorandum of understanding with Iran on the conflict’s standing issues, though congressional leaders have reported receiving minimal information about its terms or implementation. Vice President JD Vance continues to lead the U.S. delegation in Switzerland as both sides seek to resolve outstanding disputes without congressional oversight or approval.