Congress splits over Iran war as Senate faces a vote.

Secretary of State Marco Rubio speaks to reporters amid closed-door briefings for members of Congress on the ongoing conflict with Iran, at the Capitol in Washington, on Tuesday, March 3, 2026. A divided Congress was deeply split over the Trump administration’s large-scale military campaign against Iran on the eve of a Senate vote on the matter, after President Trump and top officials have offered a head-snapping series of shifting justifications for the conflict. (Eric Lee/The New York Times)

By ROBERT JIMISON and MEGAN MINEIRO

A divided Congress is deeply split over the Trump administration’s large-scale military campaign against Iran on the eve of a Senate vote on the matter, after President Donald Trump and top officials have offered a head-snapping series of shifting justifications for the conflict.

Members of the House and Senate emerged from classified briefings with top administration officials on Tuesday with divergent assessments of the case they had made for war, falling almost entirely along party lines.

Democrats said the president and his team had failed to articulate an imminent threat to justify acting without consulting Congress, while Republicans largely rallied behind the president’s decision — though some warned their support could waver should the conflict expand.

“I am truly worried about mission creep,” Sen. Chuck Schumer, D-N.Y., the minority leader, said as he exited a classified briefing with Secretary of State Marco Rubio and Gen. Dan Caine, the chair of the Joint Chiefs of Staff. He said the closed-door meeting was “very unsatisfying” and that the administration had “different answers every day” about why the president ordered the strikes on Iran.

Republicans largely praised the operation, which they said prior presidents had been unwilling to initiate to eliminate the threat posed by Iran. Some warned that a prolonged military campaign could risk eroding that backing.

“I’ve never felt better about how this ends,” said Sen. Lindsey Graham, R-S.C., who emerged from the briefing before it concluded lauding the administration’s actions and rationale.

The partisan rift was on display ahead of a Senate vote expected on Wednesday, and a similar one planned in the House on Thursday, on measures that would curb Trump’s power to continue using military force in Iran without explicit authorization from Congress. Both were expected to fail given almost unanimous Republican opposition.

But the debate was likely to give voice to a deep well of anxiety and uncertainty on Capitol Hill about Trump’s decision, without consulting the legislative branch, to start what he and his advisers have characterized as a potentially open-ended conflict in the Middle East.

As he arrived for a second day of closed-door meetings with lawmakers on Tuesday, Rubio said the United States was preparing to intensify attacks on Iran in the coming days. He warned Americans in the region about the risk of retaliatory strikes, urging them to leave as airports closed and embassy staff members were evacuated.

A day after asserting that the decision to strike Iran was driven primarily by Israel’s plan to attack the country, leaving U.S. interests vulnerable to retaliation, Rubio walked back that rationale. He said Tuesday that Trump had determined that the threat posed by Iran’s growing weapons arsenal constituted an imminent danger to Americans in the region.

But in a legally mandated letter to Congress, Trump asserted that he ordered the sweeping airstrikes to advance national interests and eliminate Iran as a global threat, contradicting his own officials’ claims of an imminent threat. The letter said the attack aimed to “neutralize Iran’s malign activities.”

Several lawmakers exited the closed-door briefing expressing deep skepticism about the rationale.

“We got no additional information on what the imminent threat was,” Rep. Pramila Jayapal, D-Wash., said. “There were a lot of references to the 47 years of Iran being a problem. That is not imminent. That is in the past. Imminent means immediate threat to the U.S.”

Rep. Sara Jacobs, D-Calif., said that administration officials had “pushed back on the idea that Israel was calling the timing. But then they kind of said that Israel was calling the timing. So it was all very incoherent.”

Republican leaders struggled to echo the administration’s conflicting explanations. On Monday, House Speaker Mike Johnson told reporters after an initial classified briefing for congressional leaders with Rubio that the “great concern” was that, in the wake of an Israeli attack, U.S. troops would have been the target of Iranian retaliatory attacks.

“We would have suffered staggering losses,” Johnson said. “And if we had waited to respond, before acting first, then those losses would have been far greater.”

But on Tuesday, he echoed Rubio’s new explanation, telling reporters: “This is really a very simple matter. It’s about the building of ballistic missiles. That’s what Iran was engaged in. And they were doing it at a speed and at a scale that was exceeding the ability of our regional allies to respond appropriately. This created an imminent and serious threat.” He made no mention of Israel.

Still, even as they prepared to vote against the measure to rein in Trump’s war powers, some Republicans suggested their position could shift if the military action expanded or dragged on.

“I will be a no for now, but if this thing goes beyond a few weeks, I’m going to have a lot more concerns,” Rep. Nancy Mace, R-S.C., said after the briefing Tuesday. She added that her concerns would grow if U.S. troops were deployed on the ground in Iran, but noted, “That’s not where we are today. That’s not what I heard in the briefing.”