"As for Craig staying in the Senate, why shouldn't he?"

Quite possibly, no reason. Trouble is, he pled guilty to a charge. It appears that the charge was a misdemeanor (minor offense) and he very well might ride this thing out.

"Bush and Cheney have broken much more important laws and the Republicans are not calling for them to resign.

Well, that where the difference between having pled guilty to a charge, and being charged with something and being found guilty comes into play. Political enemies of Bush and Cheney are convinced of their having broken laws but this is still a country where one has to be charged and prosecuted and found guilty in a court before disciplinary actions can be taken. I'm sure that if Bush and Cheney can be found guilty of something, there will be consequences for them.   

"If he stays and makes it through the Republican primary next year, we'll see whether Idahoans hate gays (and/or bathroom cruisers) more than they hate Democrats.

Do you "hate" your political opponents? I'm just curious because I don't. I don't vote for someone because I hate his opponent. I don't vote against someone because I hate him. Hate doesn't really ever enter the political picture for me. I guess I had assumed the same of Democrats -- the ability to disagree without hating.