Donald Trump’s obsession with antifa surfaced again Wednesday as the president announced that he was designating the loose-knit anti-fascist political movement as a “major terror organization.”

That phrase does not appear in U.S. law or federal regulations, but legal niceties did not stop Trump from making a nearly identical announcement during the Black Lives Matter protests in 2020.

While there’s no legal mechanism allowing the Trump administration to directly label a domestic terror group, experts warn that the Trump administration could still try to find creative ways to put American activists in court or under financial pressure by tying them to foreign groups.

As Trump and allies try to use last week’s assassination of Charlie Kirk to paint left-wing groups with no ties to the alleged killer as threats to the country, the larger danger may stem from the very looseness of the term antifa, warned Mark Bray, a historian and author of “Antifa: The Anti-Fascist Handbook.”

“There is a kind of paradox. Because on the one hand, it is so vague that how could they make a law designating antifa as a terrorist organization? It’s a broad politics, it’s not a specific organization,” Bray said. “On the other hand, the broadness and the lack of a concrete, overarching organization could allow the Trump administration or judges or prosecutors to label as antifa anyone on the left, particularly the radical left.”

The White House did not respond to a request for comment Thursday.