President Donald Trump on Wednesday announced he was designating the anti-fascist movement antifa a “major terrorist organization,” a move that follows last week’s assassination of conservative leader Charlie Kirk.
Trump posted the declaration on Truth Social while on a state visit to the United Kingdom, hours after attending a state banquet at Windsor Castle.
“I am pleased to inform our many U.S.A. Patriots that I am designating ANTIFA, A SICK, DANGEROUS, RADICAL LEFT DISASTER, AS A MAJOR TERRORIST ORGANIZATION,” Trump wrote, adding that he would “strongly recommend that those funding ANTIFA be thoroughly investigated in accordance with the highest legal standards and practices.”
The announcement comes amid a heightened crackdown by the administration on groups it says are fomenting political violence.
The designation was explicitly tied by senior officials to the killing of Kirk at a university event, a killing that has intensified partisan pressure in Washington.
Authorities say the 31-year-old Kirk was shot while speaking at Utah Valley University last week; prosecutors have charged a 22-year-old suspect in the death. The shooting has prompted a flurry of political responses across the spectrum.
Legal experts say the move raises immediate and daunting legal questions. There is no established federal mechanism for designating a loose, decentralized political movement such as antifa as a domestic terrorist organization in the same way the State Department lists foreign terrorist organizations.
Past fact-checking and legal analysis have noted presidents cannot unilaterally declare a domestic political movement a terrorist group in the way foreign organizations are designated. Any attempt to treat a U.S.-based, leaderless movement as a formal terrorist organization would likely face prompt court challenges.
Congressional Republicans have for months pushed measures to classify antifa-linked conduct as domestic terrorism; a House resolution introduced earlier this year urged the Justice Department to prosecute antifa-linked violence and called for a legislative pathway to treat certain Antifa conduct as terrorism. But analysts say the resolution does not create the statutory tools necessary for a formal domestic terrorist designation.
Administration officials signaled they may pursue multiple avenues beyond a formal label: expanded criminal prosecutions, tighter scrutiny of nonprofit and donor networks, and potential use of racketeering statutes to go after coordinated campaigns of violence.
Civil liberties groups warn that such strategies risk sweeping up lawful protest activity and could chill protected speech. Dozens of liberal nonprofits have already pushed back, accusing the administration of trying to exploit the Kirk killing to criminalize dissent.
The announcement is sure to deepen partisan divides.
Supporters hailed the move as a necessary response to politically motivated violence; opponents described it as an overreach that threatens constitutional protections. Legal scholars say a near-term showdown in federal courts is likely if the administration follows through with sanctions, investigations of donors, or expanded criminal charges tied to loosely affiliated activists.
White House officials said they will brief Congress and law-enforcement partners this week on next steps.
Analysts note that designations tied to domestic movements historically collide with First Amendment protections and the structural limits of executive authority — making the practical effect of the announcement uncertain unless backed by new legislation or narrow, evidence-based prosecutions.