That if he doesn't drag Trump across the finish line, it'll be the start of a final decline for conservatism as a political concept and that the Republicans will never hold the presidency again thanks to their compound failures becoming impossible to ignore.
Which has the strong possibility of causing a self fulfilling prophecy, that if this blows up in their face, they will have caused the very thing they were avoiding. And be much worse off than if they let it sputter out gracefully.
Republicans have tied their entire coalition to white people and Christians (ideally both at once). Guess which two groups are declining drastically, largely from self-inflicted failures. This won't be a final victory for them either, but he hopes to slow it down.