Seeing this, I think you're mistaken. The system and culture of US governance have over time changed to accommodate fascism. It is now doing exactly what it mutated into because Trump's the amorphous glob that could slot into the void that kicked all the gears into motion. Trump didn't start ICE.
Trump didn't create the current corporate media environment that is doing its level best to sanewash and hide what's happening. Trump didn't create the Republican party as it currently exists. Authoritarian and xenophobic, actively hostile to facts and expertise. Trump didn't create the Democrats.
Someone else, since early Cold War, vested the President with sweeping 'Emergency Powers,' ill-defined.
Goes back farther. Congress started seeding the presidency with emergency powers in the 20s and 30s. Wilson and FDR increased the power of the executive to higher levels. Eisenhower helped make congress more comfortable with empowering the executive. Nixon finally made it normal.