As far as I can tell the Trump White House didn't invoke any specific (Congress) laws for declaring Antifa a 'domestic terrorist organization' in an Executive Order, as EOs sometimes if not usually do [invoke Congress legislation]. Not surprising since a bunch of those e.g. 18 U.S.C. 2339B only seem to cover foreign terrorist organizations. Perhaps the WH wants to argue that that power to declare domestic terrorist threats is inherent in the Constitution, as they say Antifa "explicitly calls ...
