On September 17, 2025, U.S. President Donald Trump announced his intention to designate the anti-fascist movement known as Antifa as a “major terrorist organization.” The announcement, made via a post on his Truth Social platform, described Antifa as a “sick, dangerous, radical left disaster.” This move follows the recent assassination of right-wing commentator Charlie Kirk, which Trump and his administration attribute to a broader “domestic terror movement” driven by left-wing activists.
Background on Antifa and the Announcement
Antifa, short for “anti-fascists,” is not a single organization but a loosely organized network of activists who oppose far-right ideologies, often confronting groups like neo-Nazis at protests. The movement lacks a formal leader, structure, or membership list, which raises questions about how the Trump administration plans to apply the terrorist designation to such a decentralized group.
Trump’s statement came during a state visit to the United Kingdom, where he reviewed the Guard of Honour at Windsor Castle on September 17, 2025. In his post, he also called for a thorough investigation into those funding Antifa, stating, “I will also be strongly recommending that those funding Antifa be thoroughly investigated in accordance with the highest legal standards and practices.”
Context of the Kirk Assassination
The announcement follows the killing of Charlie Kirk, a prominent conservative commentator, allegedly by 22-year-old Tyler Robinson from Utah. While investigators have not yet confirmed a motive, many on the political right, including Trump and his allies, have pointed to leftist ideology as the driving force behind the assassination. Stephen Miller, the White House deputy chief of staff, vowed to “uproot and dismantle these terrorist networks,” channeling outrage over Kirk’s death into a broader crackdown on left-wing activism.
Republican Senator Bill Cassidy of Louisiana supported Trump’s decision, stating, “Antifa seized upon a movement of legitimate grievances to promote violence and anarchy, working against justice for all. The President is right to recognize the destructive role of Antifa by designating them domestic terrorists.” Cassidy had previously co-sponsored a 2019 Senate resolution with Senator Ted Cruz to condemn Antifa’s actions and label them a domestic terror group.
Legal Challenges and Criticism
Legal experts have raised concerns about the feasibility of designating Antifa as a terrorist organization. Unlike foreign groups like the Islamic State or al-Qaeda, which can be placed on the State Department’s list of foreign terrorist organizations, domestic groups like Antifa are protected by broad First Amendment rights in the United States. Mary McCord, a former senior Department of Justice official, noted during Trump’s first term that there is no legal mechanism for designating domestic organizations as terrorist groups in the same way as foreign entities. She warned that such a move could raise significant free speech concerns.
Critics argue that the Trump administration is using Kirk’s killing as a pretext to target political opponents. The lack of a clear structure within Antifa complicates efforts to label it a terrorist organization, as it is more an ideology than a formal group. In 2020, then-FBI Director Christopher Wray testified that Antifa is “an ideology, not an organization,” further highlighting the challenges of applying such a designation.
Historical Context
This is not the first time Trump has targeted Antifa. During his first term, in the wake of nationwide protests following the killing of George Floyd in May 2020, Trump accused Antifa of orchestrating violent demonstrations and threatened to designate it a terrorist organization. At the time, legal scholars dismissed the move as legally unfeasible, and no formal designation was made.
Broader Implications
Trump’s announcement coincides with other recent controversies, including the indefinite suspension of Jimmy Kimmel’s late-night show after comments he made about Kirk’s killing. Kimmel’s remarks, which criticized efforts to distance the shooter from conservative ideologies, prompted backlash from Trump supporters and led to ABC’s decision to preempt the show following pressure from the Federal Communications Commission and Nexstar, a major owner of local ABC stations.
As the Trump administration moves forward with its plans, questions remain about how it will navigate the legal and practical challenges of targeting a decentralized movement like Antifa. The designation could set a precedent for how the government addresses domestic activism, raising concerns about free speech and the potential for political overreach.