That's why I favor building a labor party and splintering the Democrats away from their shitty party. Their party is full of people who do not belong and would be more at home in a different party, if we had a system that wasn't so unfavorable to third parties.
The only choice is to replace the Democrats as the only other party. Let all the right-wing Democrats join the Republicans and we build a new party with everyone who is left.
Seems... Impossibly hard to do though.