It looks like the confirmation of Brett Kavanaugh was the last straw for a lot of Republicans. In this piece from The Atlantic, Tom Nichols writes:

“I’m out. The Trumpers and the hucksters and the consultants and the hangers-on, like a colony of bees who exist only to sting and die, have swarmed together in a dangerous but suicidal cloud, and when that mindless hive finally extinguishes itself in a blaze of venom, there will be nothing left.”