Donald Trump’s path of destruction has pushed the Republican Party to the cusp of a historic reckoning, an existential crisis that has left half of America’s political establishment in desperate need of new leaders, a new message, and even a common orthodoxy. “It’s like Humpty Dumpty fell and broke, then a giant lawn mower ran over it, acid was thrown on the pieces — and a bunch of racist idiots ran off with an arm and a leg,” said John Weaver, a longtime Republican consultant. “This is kind of like a forest fire,” said Dan Judy, a veteran Republican pollster who has worked for Senator Marco Rubio. “Either something healthier is eventually going to grow back from it, or it’s just going to burn everything down to the ground. I’m just not sure which it’s going to be yet.”