Senate Democrats are panic breathing because they face the voters in two years under circumstances unlikely to change a lot in their favor. The president shows no willingness to compromise, and hard left thinks electoral gold is to be found by moving the party further to the edge.
Party pragmatists understand that in a country with 21% self-identification of voters as either "liberal" or "very liberal," moving farther left is death. But they have the same lemming like march to purity that many in the GOP have displayed.
Successful leaders understand that party ideology has to be expansive in order to maximize supporters; the current administration thinks that is spinach and wants none of it.