I asked several top Republican strategists who have worked on presidential campaigns but are not involved in this one. None believes Trump will win, but most thought a congressional stampede would not be decisive, or even terribly important.

“It is not going to become unsurvivable for Trump,” wrote one. “It already is unsurvivable for Trump.” Nevertheless: “I don’t think congressional defections matter in terms of Trump’s fate one bit. The die is now cast for him. Congressional defections are all about the defectors trying to save themselves from the flying shrapnel.”

“This is not about whether it is survivable for Trump,” wrote another. “Much of this is already built into his stock price. He may not win, but he’s driving the wagon and will continue to do so. Others riding in his wagon may not be so lucky. They are bailing because they can’t afford to go down this road with him.”

One good sign for the party, some believe, is that voters don’t really see Trump as a Republican, or at least as a Republican like the Republicans they support for House and Senate. Perhaps it’s a comforting bedtime story Republicans tell themselves, but many believe the voters will distinguish between Trump and the rest of the party on election day, and those down-ballot Republicans will do well even as Trump fails.