As the conflict between Israel and Iran enters its fifth day, pressure is mounting in Washington over whether the United States should escalate its involvement. While President Donald Trump has so far framed recent U.S. troop deployments to the Middle East as defensive, many in Congress are warning that any further military action must be authorized by the legislative branch—not decided unilaterally by the White House.

On Monday evening, Trump abruptly left the G7 summit and issued a stark warning to Iran, urging everyone to evacuate Iran. He That same day, U.S. military forces were repositioned in the region, signaling growing concern over a broader regional war. Yet politicians on Capitol Hill are moving quickly to assert congressional authority over any potential escalation.

Rep. Massie and Rep. Ro Khanna announced plans to introduce a resolution on Tuesday that would require President Trump to obtain congressional approval before engaging in military action against Iran. “This is not our war. But if it were, Congress must decide such matters according to our Constitution,” Massie posted on X. Progressive Rep. Alexandria Ocasio-Cortez lresponded, “Signing on.”

The measure has drawn early support from lawmakers across ideological lines, including several who have been critical of U.S. foreign policy in the Middle East. Democratic Senators Bernie Sanders, Elizabeth Warren, and Chris Van Hollen are backing parallel efforts in the Senate.

Sen. Tim Kaine on Monday introduced a war powers resolution aimed at curbing unauthorized military action. The resolution declares that no use of force against Iran can proceed without a formal declaration of war or specific congressional authorization. As a “privileged” resolution, it must receive prompt debate and a vote in the Senate.

“I am deeply concerned that the recent escalation of hostilities between Israel and Iran could quickly pull the United States into another endless conflict,” Kaine said. “This resolution will ensure that if we decide to place our nation’s men and women in uniform into harm’s way, we will have a debate and vote on it in Congress.”

Sen. Sanders echoed that concern, introducing separate legislation that would prohibit the use of federal funds for any military operation against Iran without congressional consent, except in cases of self-defense. “Another war in the Middle East could cost countless lives, waste trillions more dollars and lead to even more deaths, more conflict, and more displacement,” Sanders said in a statement. “I will do everything that I can as a Senator to defend the Constitution and prevent the U.S. from being drawn into another war.”

While the White House has not formally responded to the proposed resolutions, Trump’s recent actions suggest a willingness to project American power in support of Israel—while avoiding, for now, direct engagement. Whether Congress will succeed in slowing or halting that momentum may hinge on whether lawmakers from both parties are willing to reassert their war-making authority in the midst of a fast-evolving crisis.