U.S. Senator Elizabeth Warren said Tuesday that President Donald Trump does not have the constitutional authority to launch military action against Iran without congressional approval, as reports suggest the administration may be moving closer to a potential conflict.
“The American people voted for lower prices, not another war in the Middle East,” Warren wrote on social media. “But Trump is itching to go to war with Iran. The Constitution is clear: the president doesn’t have the authority to start a war without Congress’ approval. I won’t support another endless war.”
The American people voted for lower prices, not another war in the Middle East.
— Elizabeth Warren (@SenWarren) February 19, 2026
But Trump is itching to go to war with Iran.
The Constitution is clear: the president doesn't have the authority to start a war without Congress' approval.
I won't support another endless war. pic.twitter.com/gAhqTjXwhZ
Warren’s comments came in response to a report by Axios, which cited U.S. and Israeli officials as saying preparations are underway for possible military action if negotiations fail.
According to Axios, the Trump administration has adopted a dual-track strategy of nuclear talks paired with a large military buildup in the region. The report said U.S. forces have deployed two aircraft carriers, a dozen warships, hundreds of fighter jets and multiple air defense systems to the Middle East. More than 150 U.S. military cargo flights have also moved weapons and ammunition to the area.
Axios reported that Trump advisers met in Geneva this week with Iran’s foreign minister, Abbas Araghchi, but U.S. officials said major gaps remain. Vice President JD Vance told Fox News the talks showed some progress but warned diplomacy could reach “its natural end.”
The report quoted one Trump adviser as saying there was a “90% chance” of military action in the coming weeks if talks collapse. Israeli officials were cited as preparing for the possibility of war within days, while U.S. officials said the timeline could be longer.
Warren’s statement aligns with lawmakers from both parties who argue that Congress must authorize any military action against Iran.
Representative Thomas Massie, a Republican, said he would oppose military action and support forcing a House vote under the War Powers Resolution. Massie said the Constitution gives Congress the sole authority to declare war and argued there is no imminent threat from Iran that would justify unilateral action by the president.
“Congress must vote on war according to our Constitution,” Massie wrote, adding that he would vote against “more war in the Middle East.”
Congress must vote on war according to our Constitution. @RepRoKhanna and I will be forcing that vote to happen in the House as soon as possible.
— Thomas Massie (@RepThomasMassie) February 19, 2026
I will vote to put America first which means voting against more war in the Middle East. https://t.co/O0LcTDWNDS
Massie is working with Representative Ro Khanna, a Democrat, on a bipartisan measure, House Concurrent Resolution 38, which would direct the president to terminate the use of U.S. armed forces in hostilities against Iran unless Congress explicitly authorizes such action.
The resolution invokes Section 5(c) of the War Powers Resolution, which allows Congress to order the withdrawal of U.S. forces engaged in unauthorized hostilities. It states that Congress has not declared war on Iran or passed a specific authorization for military action against it, and that any ongoing or future hostilities must end unless lawmakers approve them.
The measure includes language clarifying that it would not prevent the United States from defending itself against an imminent attack and would not interfere with intelligence sharing or counterterrorism activities. It also specifies that it does not itself authorize the use of military force, but is intended to reassert Congress’s role before any strike or broader conflict occurs.
Khanna has said he plans to use a procedural motion to force the resolution out of committee and bring it to the House floor for a vote. “I will make a motion to discharge to force a vote on it next week,” he said.
Trump officials say there's a 90% chance of strikes on Iran. He can’t without Congress. @RepThomasMassie & I have a War Powers Resolution to debate & vote on war before putting U.S. troops in harm’s way. I will make a motion to discharge to force a vote on it next week. https://t.co/FWQ245D6B8
— Ro Khanna (@RoKhanna) February 18, 2026
Warren framed the situation as a test of Congress’s constitutional role and warned against another prolonged U.S. conflict in the region.
“There’s no evidence a diplomatic breakthrough is on the horizon,” the Axios report said, adding that signs of an imminent confrontation are increasing as military deployments expand.
Warren said she would oppose any unilateral move toward war and called on lawmakers to assert their authority before U.S. forces are committed to another large-scale military campaign.
