Until the Trump victory, the gerrymander seemed as if it was about to solve itself. Theoretically, a gerrymander is self-destructive. A safe seat can only be contested when an extreme candidate runs against a moderate one, presumably the incumbent, usually in a primary. Often such a candidate is successful, since in local primaries, only the most faithful loyalists come out to vote. The extremist attracts attention and therefore votes, while the moderate incumbent has a harder argument to make, plus the antipathy Americans have for any candidate the moment he actually takes his seat. The extreme candidate goes to office, enacts his extreme agenda (to avoid being primaried himself) and gets in trouble with the general electorate who are more moderate. It may take a couple of cycles but eventually reasonable people cross party lines and vote in the candidate from the other party, ending the gerrymander.
In the old days, machine politics prevented this. The party bosses decided who would run, so they kept the candidates moderate and distributed favors to the faithful and brought home bacon to the electorate. It’s hard to run a political machine in the modern era. People are dispersed in the suburbs. It’s hard to get to them at church, if they go to church, and if the unions are busted, you can’t get to them at work.
This situation of moderate Republicans being replaced by Tea Party extremists whose only goal in joining government was to keep it from working (like Ron Johnson on Parks and Recreation) led to John Boehner’s frustration and eventual retirement and promised headaches and eventual failure for Paul Ryan. But if the whole government is Republican then the obstructionists have to explain why explain why they are gumming up the works of an otherwise functioning government. Why are they going against the president and the Senate? What’s wrong with you people? Are you nihilists? In fact, they are, but nihilism in the face of opposition is seen as a principled position of protest. When it goes against the majority, it’s a disease that must be surgically removed.
The Democratic Party will not be outlawed; it doesn’t have to be.