A prolonged shutdown would endanger the reelection campaigns of Tester, Heitkamp, McCaskill, Donnelly, and Manchin, all of whom are needed to get to 51 after the midterms.
What do you think alienating the base is going to do? Sorry, but Dems don't win mid-terms when they aren't mobilized. And what has kept them mobilized is the Trump outrage machine(mostly justified so, if often expressed poorly by many) and the
good faith wise political calculus on the part of Democrats to fight these fights, like healthcare, like DACA, like tax cuts.
DACA enjoys majority support by both parties. A shutdown now is not going to be an issue at the end of the year broadly speaking, especially not the sort of casual swing voters that are not paying attention now.....It will count to the people that this means something to, which is the base you want to have mobilized, and the minorities that the Democratic party needs to continue making major inroads within.
But this shit should be in the politics thread.