The U.S. House of Representatives overwhelmingly passed H. Res. 1099 on Thursday, reaffirming that Iran remains the world's largest state sponsor of terrorism, with 415 members voting in favor and 53 voting against. All 53 nays came from Democrats, along with two Democrats voting present and seven members not voting.

Introduced by Rep. Brian Mast, R-Fla., on March 4, the resolution declares it U.S. policy that the Islamic Republic of Iran continues as the leading state sponsor of terrorism. It cites Iran's support for proxy groups including Hezbollah, Hamas and the Houthis, responsibility for the deaths of at least 603 U.S. service members in Iraq, assassination plots against Americans, and violations of nuclear nonproliferation obligations. The measure passed under suspension of the rules, requiring a two-thirds majority, which it easily met.

The vote occurred amid heightened U.S.-Iran tensions following the U.S. and Israeli strikes on Iranian targets, including the killing of Supreme Leader Ayatollah Ali Khamenei on February 28. Republicans framed the resolution as a necessary affirmation of Iran's long history of aggression, including the 1979 hostage crisis, the 1983 Beirut barracks bombing and recent Houthi attacks on U.S. ships.

Rep. Mast urged passage, crediting President Donald Trump's actions, such as the elimination of Qasem Soleimani, with protecting Americans from Iranian threats. "Iran has attacked America for 47 years," Mast said during debate. Rep. Julie Fedorchak, R-N.D., highlighted recent briefings underscoring Iran's nuclear ambitions and ballistic missile threats, stating the resolution sends a "strong message" against state-sponsored terrorism.

Democrats who opposed the measure, including progressive members of the "Squad" such as Reps. Alexandria Ocasio-Cortez of New York, Ilhan Omar of Minnesota, Rashida Tlaib of Michigan and Ayanna Pressley of Massachusetts, argued it was redundant since Iran is already designated a state sponsor of terrorism by the State Department. Others, like Rep. Lateefah Simon, D-Calif., called it a political stunt designed to justify ongoing U.S. military actions, containing inaccuracies and providing pretext for war. Rep. Sara Jacobs, D-Calif., noted concerns over language invoking the 2001 Authorization for Use of Military Force or Article II powers.

Notable Democrats voting no also included Reps. Joaquin Castro of Texas, Raja Krishnamoorthi of Illinois, Sarah McBride of Delaware and Robert Garcia of California. Krishnamoorthi acknowledged Iran's role in terrorism but opposed the resolution fearing it could politically justify the conflict. Rep. Adam Smith, D-Wash., supported it while criticizing war as an overreaction.

The resolution's passage followed the House's rejection of a Democratic-led war powers measure aimed at curbing presidential authority over Iran operations. Republicans held firm in opposition to such limits, aligning with the Trump administration's strategy. Iran has long been listed on the State Department's terror sponsor list since 1984, with ongoing sanctions and designations for its Revolutionary Guard Corps as a terrorist organization.