Unfortunately, while I wish your wishful thinking was more than just hope, the reality on the ground means that Trump not only will be able to ignore all Democratic efforts but will also most likely win in 2020 for the same reasons he won last time: the dull-eyed drooling mob will support him whatever he does precisely because he’s as stupid and infantile and venal as they are; vote-the-ticket Republicans will vote for him because they can’t help themselves: they’d vote for Hitler or Stalin if either of those had that magic “R” next to their name on the ballot; and the dysfunctional US Electoral College means that majorities are irrelevant.
The thing is, Trump is merely a symptom of the abject failure of representative democracy in a complex inter-connected world. That’s why we’re seeing populism everywhere: Brexit in the UK, PiS in Poland, Bolsonaro in Brazil, Le Pen in France, AfD in Germany, Erdogan in Turkey, Babic in the Czech Republic, and on and on and on around the world. US citizens fixate on Trump because the US media is incapable of providing a global perspective, but once you realize what’s happening is essentially the same everywhere you can see that Trump is merely a symptom of a far more profound problem.