"The Constitution does not permit the executive branch to unilaterally commit an act of war against a sovereign nation that hasn't attacked the United States," Massie explained in a statement. "Congress has the sole power to declare war against Iran. The ongoing war between Israel and Iran is not our war. Even if it were, Congress must decide such matters according to our Constitution."
In a post on the social media site X, Massie thanked the resolution's co-sponsors, all of them Democrats: Don Beyer (Va.), Greg Casar (Texas), Alexandria Ocasio-Cortez (N.Y.), Lloyd Doggett (Texas), Jesús "Chuy" García (Ill.), Val Hoyle (Ore.), Pramila Jayapal (Wash.), Summer Lee (Pa.), Jim McGovern (Mass.), Ilhan Omar (Minn.), Ayanna Pressley (Mass.), Delia Ramirez (Ill.), Rashida Tlaib (Mich.), and Nydia Velazquez (N.Y.).
More lawmakers—possibly including Republicans—are expected to sign on to the measure.
"The president does not have the power to unilaterally declare war. Congressional authorization isn't optional," Lee said on social media. "When some profit both financially and politically from endless war, the rest of us pay the price. We can't let them lie us into another conflict that will cost innocent lives."
Tlaib asserted that "the American people aren't falling for it again. We were lied to about 'weapons of mass destruction' in Iraq that killed millions [and] forever changed lives."
The progressive political action committee Justice Democrats welcomed Massie's measure: "Here's an opportunity for bipartisanship that doesn't sell out the American people. Every member of Congress should oppose U.S. involvement, funding, weapons, or troops fighting another endless war in the Middle East."
The House proposal follows Monday's introduction of a war powers resolution by Sen. Tim Kaine (D-Va.) and bill by Sen. Bernie Sanders (I-Vt.) that would prevent the Trump administration from using federal funds for a military attack on Iran without congressional approval. It also echoes a 2020 resolution proposed in the then-Democrat-controlled House that would have banned Trump from waging war on Iran without lawmakers' approval.
Explaining her support for Massie's legislation, Omar said, "I support this resolution because the American people do not want another war."
Indeed, an Economist/YouGov poll published Tuesday revealed that only 16% of surveyed voters "think the U.S. should get involved in the conflict between Israel and Iran." Just 10% of respondents who voted for former Vice President Kamala Harris last year and 19% of 2024 Trump voters want the U.S. to wage war on Iran, as do 15% of self-described Democrats, 11% of Independents, and 23% of Republicans.
A separate survey commissioned by Demand Progress and conducted by the Bullfinch Group recently found that 53% of registered voters—including 58% of Democrats, 47% of Independents, and 56% of Republicans—want Trump to "obtain congressional authorization before striking targets in other countries."
"We applaud Rep. Massie and Sen. Kaine for introducing these resolutions to keep us out of yet another war in the Middle East," Demand Progress senior policy adviser Cavan Kharrazian said Tuesday. "It should be in the interest of Republicans and Democrats to uphold the Constitution and prevent Israel from dragging us into a disastrous war with Iran."
"The American people, including a clear majority of Republican voters, believe the president must obtain congressional authorization before initiating strikes against another country," Kharrazian added. "Congress must listen to them and reassert its constitutional war powers authority by passing these resolutions."
Israel claims it attacked Iran to stop it from obtaining nuclear weapons. However, successive U.S. intelligence assessments have concluded for decades—most recently in March—that Iran is not trying to build nukes. On Tuesday, Trump brushed off his own director of national intelligence's findings that Iran is not close to having a nuclear bomb.
As Trump ratcheted up his cryptic threats against Tehran amid ongoing Israeli attacks on Iran and Iranian counterstrikes, anti-war voices including the National Iranian American Council (NIAC) and the peace group CodePink urged restraint and negotiation to avert escalating the Mideast crisis.
NIAC, which is circulating a petition demanding Congress act to avert U.S. intervention, is planning to hold a Tuesday afternoon No War With Iran Action Hour co-hosted with Peace Action and Action Corps.
"Trump continues to renege on his own commitments to diplomacy and an end to wars by perpetuating [Israeli Prime Minister Benjamin] Netanyahu's war of aggression through his own vocal support and U.S. military equipment and personnel in the region," NIAC said Tuesday. "Israel's assaults on Tehran have killed upwards of 224 Iranians and hospitalized over 1,277 more."
"Happening at the same time, in just the last day alone, Israeli forces have also killed at least 51 Palestinians desperate for aid and food at a World Food Program site in southern Gaza," NIAC noted. "There is no telling how much more devastation for Iran, Israel, and the U.S. an expanded war on Iran would bring."
"President Trump must immediately halt military aid and support for the Israel war on Iran," the group added, "and if he will not, Congress must act within its constitutional authority to save millions of American, Iranian, Israeli, and Palestinian lives."