US Senate votes to pass Iran war powers resolution in blow to Trump

What Happened

The US Senate voted 50 to 48 on Tuesday to pass a war powers resolution directing President Donald Trump to remove US Armed Forces from hostilities against Iran, unless explicitly authorised by Congress. The resolution, which had passed the House earlier in the month, demands a halt to Trump’s military campaign that began with US-Israel strikes on February 28 and expanded into a region-wide war, including Trump’s June 2025 bombing of three Iranian nuclear sites. Four Republicans—Bill Cassidy, Lisa Murkowski, Susan Collins, and Rand Paul—joined nearly all Democrats, while Senator John Fetterman was the lone Democrat opposed. Senate Democratic Leader Chuck Schumer lambasted the war as a historic blunder, while Senator James Risch warned the resolution would sabotage ongoing ceasefire negotiations in Switzerland, where the US and Iran are discussing a June 17 memorandum of understanding. The measure is largely symbolic, as Trump is expected to veto it.

Key Actors

Why It Matters

The vote crystallises a constitutional clash between Congress and the executive over warmaking powers, while exposing cracks in Republican support for Trump’s Iran strategy. Although a veto will likely render the resolution moot, the bipartisan passage underscores growing alarm over an undeclared, escalating war that has drawn in Israeli strikes in Lebanon, violating the ceasefire terms, and could destabilise the region further. It also complicates Trump’s diplomatic leverage in ongoing Switzerland talks, as Tehran may perceive American resolve as fractured.

Watch For

Monitor whether Trump vetoes the resolution and if Congress attempts—and fails—to override. Track the Switzerland ceasefire negotiations, especially given Israeli strikes in Lebanon that breach the June 17 MOU. Watch for any new US or allied military operations, Iranian reactions, and shifts in non-state actor activity (Hezbollah, Houthis) that could upend the diplomatic track.