Lately Carl Paladino, the unsuccessful Republican candidate for governor of New York in 2010, has lately been attacking other Republicans for insufficient ideological purity and predicting their doom. He puts a lot of these rants into open emails to party leaders he dislikes, and some of them reply in public as well.
While public email fights are almost always boring and annoying to onlookers, there's something to be said for this one, which approaches the sort of exchange you might expect between battling characters in a Marvel comic. I particularly enjoyed reading a hilarious mocking rant from the head of the Albany County Republicans to Paladino, inter alia asking him to "please crawl back into your clown car and drive it back into the hole you came out of."
You can read excerpts from and commentary about Paladino's war with the rest of his party here, which has links to more material.