I'd makes sure a (seemingly) populist candidate--maybe a woman or a 'minority'--were ensconced at the helm of the ship of state when the "perfect" storm was coming: multiple international wars of aggression, domestic economic distress, planetary climate disaster, massive social upheaval, unprecedented unemployment, failed health care debacles, metastacizing energy crises, insoluble immigration conflicts, and unending border wars.
I'd make sure that that the new 'leader' had campaigned on a 'vision of change." Had promised to 'fundamentally transform" the system. Had touched and tapped all the hot, progressive issues.
I'd make sure s/he won with a smallish mandate, big enough to appear convincing, but still small enough to ensure paralysis. I'd be sure that the new 'leader' had a plausible (albeit worthless) "majority" in Congress, the "appearance" of power, without its perqs.
I'd make sure that his opposition was still basically in tact, and in charge of the agenda, and that the press was still TOOTHLESS corporate stooges and stenographers for the special interests, the captive lapdogs of the status quo; but that they'd use the new guy to demonstrate their independence.
I'd use that 'press' to (illegitimately) assign blame for the crises with the New Guy, on the principle that the 'corporate memory' of the electorate was about as long and attentive as a butterfly in a fruit-tree.
And I'd make sure the array of crucial, vital, civilization-threatening problems was both overwhelming and endless.
And then I'd sit back and wait.
Four years aren't that long, and at the end the fascists will again be in power, and such progressives as still remain will be thoroughly discredited by the failures of the regime to "fix" the problems.