The Senate is scheduled for an initial procedural vote Wednesday on a resolution aimed at preventing President Donald Trump from authorizing additional military strikes against Iran without congressional consent. This vote represents the first official gauge of legislators’ desire to constrain an escalating conflict initiated by the President without their approval.

Sponsored by Sen. Tim Kaine of Virginia, the resolution cites the 1973 War Powers Resolution in a bid to compel Congress to reassert its constitutional power to declare war. While it has support from a majority of Senate Democrats and at least one Republican—Kentucky’s Rand Paul—the measure is almost guaranteed to fail, following the fate of seven other war powers resolutions introduced since last summer.

Republicans, who hold the majority in both the Senate and House, have mostly united in support of the President. “We should let him finish the job,” stated Sen. Lindsey Graham of South Carolina on Tuesday, endorsing a U.S.-Israeli air campaign that started five days ago and has already led to American casualties and hundreds of other deaths, including that of Iran’s Supreme Leader Ali Khamenei.

A parallel situation is unfolding in the House, where a separate war powers resolution is anticipated to come to a vote Thursday. Speaker Mike Johnson on Wednesday equated supporting the measure with siding “with the enemy,” and stated he has sufficient votes to block it.

Even if both chambers passed the resolution, Trump could exercise a veto. Overriding a presidential veto demands a two-thirds majority in both the House and Senate. Congress has never successfully overridden a presidential veto of a war powers resolution.

This vote occurs as Democrats express growing frustration, accusing Trump of increasingly excluding Congress from war-related decisions. During his second term, the U.S. military has conducted strikes without Trump seeking lawmakers’ authorization, with the administration contending he possesses inherent constitutional authority as commander in chief and is acting within current legal boundaries.

Enacted in 1973 following the Vietnam War, the War Powers Resolution was created to curb exactly this type of unilateral executive action. It mandates the President inform Congress within 48 hours of committing U.S. forces to hostilities and prohibits those forces from remaining in such conflicts for more than 60 days—with a potential 30-day extension—absent a declaration of war or specific authorization for military force. It also enables any member of Congress to force a vote on a resolution to withdraw U.S. forces.

Trump did submit a legally mandated notification letter to Congress on Monday, several days after ordering extensive airstrikes on Iranian targets. However, in the letter, he characterized the mission as promoting national interests and eradicating Iran as a global threat—wording that contrasted with the administration’s public assertions that the strikes were needed to prevent an imminent danger to American troops and allies in the region.

This inconsistent justification has increased doubt among Democrats, many of whom left classified briefings on Tuesday stating they were not persuaded the administration had shown an immediate threat warranting the bypass of Congress.

“I am truly worried about mission creep,” Senate Minority Leader Chuck Schumer remarked after Tuesday’s briefing, labeling the session “very unsatisfying” and condemning what he called varying explanations provided on different days.

Lawmakers reported that Secretary of State Marco Rubio and Defense Secretary Pete Hegseth cautioned during the briefing that military operations might escalate in the near future. At one juncture, Rubio publicly indicated the strikes were motivated by Israel’s intentions to attack Iran and worries that U.S. forces could suffer retaliation. Subsequently, he and others stressed Iran’s ballistic missile program as a pressing and grave threat. In other forums, the President has portrayed the mission more expansively as an initiative to “neutralize Iran’s malign activities.”

“I am more fearful than ever, after this briefing, that we may be putting boots on the ground,” said Democratic Sen. Richard Blumenthal of Connecticut following Tuesday’s classified briefing.

Republicans, in contrast, predominantly upheld the President’s authority. Sen. Josh Hawley of Missouri said he believed the Trump Administration was acting within the 60-day period allowed by the statute and would vote against the resolution. However, he and others hinted that their support could change if the operation broadened or prolonged, especially if American ground troops were deployed into Iran.

Democratic support for the war powers resolution is not unanimous. Pennsylvania Sen. John Fetterman has declared himself a “hard no,” contending that revoking the President’s authority in the middle of a campaign would convey a detrimental message. In the House, Democratic Reps. Josh Gottheimer of New Jersey, Jared Moskowitz of Florida, and Greg Landsman of Ohio have signaled they will vote against the resolution but would support a more restricted alternative granting the Administration 30 days to conclude operations before seeking authorization.

The procedural vote on Wednesday will show if any Senate Republicans are prepared to defy party leadership to move the measure forward. Assuming full attendance, at least four would need to side with Democrats and Rand Paul for it to pass the chamber. Even if that occurs, some might change their stance on the final vote, as happened earlier this year during a comparable debate over Venezuela after the president publicly criticized them.

For Kaine and his supporters, the short-term outlook is bleak. Yet they maintain that compelling lawmakers to take a public stand is in itself a move toward reestablishing Congress’s authority over matters of war. “If you don’t have the guts to vote ‘Yes’ or ‘No’ on a war vote,” Kaine said this week, “how dare you send our sons and daughters into war where they risk their lives?”