Former Antifa activist Gabriel Nadales praised President Donald Trumps executive order designating Antifa a domestic terrorist organization, telling Fox News the step was long overdue."This is a long time coming, and I hope that Congress really follows suit and helps define what this means," Nadales said Tuesday on "Fox & Friends First."His appearance on the Fox News Channel came days after Trump signed an executive order with the formal designation, asserting that the left-wing activist group poses a direct threat to the U.S. government, law enforcement and rule of law.MEET THE RADICAL DC ACTIVIST MOBILIZING GANG MEMBERS, 'HARDCORE MEN' TO TARGET FEDERAL TAKEOVER: 'REAL ENEMY'Nadales, who has said he left Antifa as his political beliefs shifted, said Trump's order means that many of the "self-described" and "localized" groups under the Antifa umbrella could now be labeled domestic terrorist organizations."There's this idea that Antifa is merely an idea and, to an extent, that is true, but Antifa is a very collective or a specified set of ideas that believes in political violence to enact its own political goals. That is literally the definition of terrorism," he said."So if you call Antifa just an idea, it is literally the idea of terrorism itself."Trump's order branded Antifa as a "militarist, anarchist enterprise that explicitly calls for the overthrow of the United States government, law enforcement authorities, and our system of law."DAVID MARCUS: DEMOCRATS MUST STOP THEIR DEADLY ANTI-FASCISM COSPLAY"It uses illegal means to organize and execute a campaign of violence and terrorism nationwide to accomplish these goals."Antifa claims to be an "anti-fascist" movement that also opposes white supremacy and far-right extremism.The group, however, has come under fire for wearing all black and concealing their identities and using tactics like doxxing, violence and intimidation.Nadales said giving Antifa the "domestic terrorist" label could have two effects: first, helping law enforcement address what he called "terror cells," and second, launching a public-relations battle challenging the groups identity as "anti-fascist.""Antifa continues to claim itself as the anti-fascist, and [say], 'If you are against Antifa, you're pro-fascist,' but nothing can be further from the truth," he said."To combat Antifa is to combat political violence, no matter where it comes from, because, to a great extent, a lot of these Antifa activists, they are themselves the terrorists, they are themselves the fascists, so labeling them as domestic terror groups, it really helps in the battle against Antifa in the PR realm, because it really shows them for what they are. They are a domestic terrorist movement."Fox News' Alexandra Koch and Sophia Compton contributed to this report.