If they aren't going to put anyone else on the ballot a la New Jersey, then that withdrawal doesn't make any sense...
Unless, the Dems have "the pictures" and the race is going to get even slimier and he doesn't want to endure that public humiliation.
If it is simply that he is gay, as is our Arizona Senator, then he should just own up, and say "Yes, I am, and a. I am not practicing because I believe it is wrong, or b. I do not think that is a valid reason to attack a candidate."
Either way, I think he would garner respect if not support, and the election results wouldn't be any different.
So, maybe there are more pictures out there and that is why he withdrew.
But a write in hasn't got a prayer. People should just vote for the current candidate who withdrew just to protest the attack ads if nothing else.
Only Racicot could have beat Baucus, and he has withdrawn from political elections and political appointments that require Senate approval, perhaps for similar reasons, that is, that the Dems would wage a slime attack on him and his kids aren't adults yet and he doesn't want to put his kids through that.