Feelings aside, what would be the difference?

[Anomalocaris]

What I'm asking myself is, if that's the most primitive president in American history? I feel safe in saying he's the most primitive after WWII, but I have next to no knowledge of the ones coming before FDR.

No other American president had ever been so primitive as to have had absolutely no public service experience of any sort whatsoever prior to becoming president, and lunched his bid for the supreme office upon a base of absolutely nothing beyond success in serving own greed, educated himself for not a second about the laws and traditions of the office he seeks, and then gained office through such pure unadulterated demagoguery.

I am 85% certain trump will be impeached.  Even the republicans are mortally afraid of foreign policy calamities that drastically hurt their portfolios.  But that would not stop or even slow the decline of American democracy.

America is rapidly degenerating into the late roman republic where a gulf opened between the white plebeians who think they are entitled to bread and circus for being born white and American, and most educated, professional or public service classes.  Into the gulf stepped the inevitable rich and crass demagogue. The downfall of the demagogue will not heal the rift, instead it would further embitters the deeply and irreparably debased plebeians, and create even deeper and violently hostile power struggle amongst the temporarily triumphant patricians who now have nothing to lose from the most naked and violent of power plays.  

Unlike republican room, there are plenty of powers in the world capable and eager to hurry American along on her way towards economic and geopolitical downfall.  Rome replaced a failing republic with a world empire primarily for the lack of real peer power competition. American will likely wither into island banana republic that can only occasionally exercise some bullying power over Canada and Mexico.  But what form of government the US will have who knows.