Why? Congress is majority republican, who have been under selection pressure to be party faithful. If that fails, they are getting death threats to stay in line

Why? Congress is majority republican, who have been under selection pressure to be party faithful. If that fails, they are getting death threats to stay in line. The Republican strategy is to punish bi-partisan efforts. From a Dem standpoint, its simpler to point out the fact that they have no real power, and let the Republicans take the heat. What can Congress do?