With the U.S.-Israel operation against Iran widening, the Senate voted 53-47 on Wednesday afternoon — largely along party lines — to block a procedural vote on a war powers resolution that would have forced the immediate withdrawal of U.S. forces from combat with Iran.

Sens. Rand Paul (R-KY) and John Fetterman (D-PA) broke with their respective parties as expected, with Paul voting for and Fetterman voting against the motion, with all other lawmakers voting along party lines.

The vote showcased how the Iran war has quickly become a partisan issue, despite lawmakers on both sides of the aisle expressing long-standing concerns about the threat from Iran and its malign activities and some Democrats offering a degree of positive commentary about the U.S. strikes.

Though widely expected to fail, Democrats view the resolution, and a similar one up for a vote in the House tomorrow, as a critical avenue to go on record with their opposition to the Trump administration’s military offensive. Many Democrats believe U.S. military engagement in Iran will be politically unpopular in a midterm election year, and are objecting to the administration’s decision not to seek congressional authorization for the operation.

Pressed by Jewish Insider in the days leading up to the vote, several top Democrats backing the resolution did not offer a clear articulation of the potential implications and impacts the resolution would have when U.S. assets and embassies are actively under fire from Iran.

Two argued, in spite of the directive contained in the legislation for U.S. forces to immediately withdraw, that the resolution would nevertheless allow for an orderly completion of the mission and drawdown of U.S. personnel.

Around 40 Democratic senators — most of the caucus — sat together at their desks on the Senate floor as the vote began, a break with usual Senate practice, which sees senators mingle on the floor and filter in and out of the chamber as votes proceed.

The tactic was likely designed to signal the nearly unified Democratic opposition to and concern about the legislation.

Republican Sens. Jerry Moran (R-KS), Lisa Murkowski (R-AK) and Susan Collins (R-ME) had all declined to tell reporters, in the days before the vote, how they planned to vote, but all three ultimately voted with their party against the motion. 

Sen. Todd Young (R-IN), a prominent Republican advocate for reclaiming congressional war powers, said in a statement earlier Wednesday that he believed, based on the information he received, “there was a very real possibility of Iran escalating those threats against us and our service members, so President Trump made the difficult decision to direct strikes.”

He said the danger to U.S. forces and allies “will only grow if we limit the President’s military options at this critical moment. An abrupt disengagement could pose increased risks to American lives and interests.”

At the same time, he also called for hearings and debate about the administration’s aims and strategy, particularly as the war continues.

Collins said in a statement, “Passing this resolution now would send the wrong message to Iran and to our troops. At this juncture, providing unequivocal support to our service members is critically important, as is ongoing consultation by the Administration with Congress.”

Sen. John Curtis (R-UT) said after the vote, “I will say very clearly: Yes, I wish I would have been consulted. I wish my vote would have been asked for before this. But the president did act within his legal bounds to do what he has done.”

Murkowski, Collins, Paul, Young and Sen. Josh Hawley (R-MO) recently voted with Democrats in favor of a procedural vote on a similar resolution to end U.S. operations in Venezuela, but Hawley and Young ultimately flipped on the vote on the resolution itself, leading the Venezuela resolution to fail.

Paul argued that the war in Iran was contrary to Trump’s campaign message of opposing regime change and preemptive wars, which he said had resonated with him and with other Trump voters.

The general GOP unity around the resolution isn’t necessarily a signal that all Republicans are directly in lockstep behind Trump’s efforts, however, or that they would remain so regardless of how the campaign proceeds.

Hawley — who generally favors a more restrictionist foreign policy — for example, told reporters on Tuesday that he believed Trump would need congressional approval to put troops on the ground in Iran. But Sen. Rick Scott (R-FL) offered the opposite view.

Collins said in a statement that “sustained combat operations require full engagement with Congress. The Administration has adhered to the provisions of the War Powers Act that require notification to Congress within 48 hours of hostilities commencing, and it has provided numerous classified briefings to Congress.”

Some former Democratic officials have questioned the wisdom of the approach taken by the war powers resolutions up for debate in the Senate and House, which demand the immediate withdrawal of U.S. forces from combat with Iran.

They’ve argued that it’s unreasonable, unrealistic and dangerous for U.S. forces to be required to pull out immediately, without any drawdown period.

“We have U.S. servicemembers in harm’s way. Some are flying combat sorties as we speak. We can’t call them in the cockpit and say ‘Congress has prohibited you from completing this mission. Please turn around and stop what you’re doing.’ If that sounds a little strange, it is because the Ro Khanna [D-CA] resolution requires that very strange outcome,” Jeremy Bash, a former chief of staff at the Department of Defense and Central Intelligence Agency under the Obama administration, told JI, referring to a similar resolution in the House.

“An immediate withdrawal is dangerous for our troops. Any pullback needs to be orderly and safe. We need to give the combatant commander at least a few weeks to do this safely,” Bash continued. “For a war powers resolution to be credible, it has to build in several days for the commanders to act responsibly to protect their troops. This cannot be done immediately.”

Without congressional authorization, the administration is required under law to end the operation 60 days from its start.

The House is set to vote on similar legislation tomorrow, with most lawmakers again expected to vote along party lines.

The vote was held open for an extended time to allow Sen. John Cornyn (R-TX) to return to the Senate after his Tuesday night primary election. 

Washington reporter Matthew Shea contributed reporting.