Over the long term, the Democrats will invoke the nuclear option in a heartbeat and never once think anything of it.
Meanwhile, I maintain that the reason that McCain is the darling of the liberal press is for two reasons:
1. He can be pushed into attacking the President and other Republicans, which the press loves.
2. The press is salivating for him to get the nomination, at which point they will immediately turn on a dime and print all the dirt they have on him, which is a lot.
McCain is too stupid to see this.