There just are only a handful of republicans who hold state wide office. The most likely challenger (and it's none too likely) is Tom Salmon, the state auditor. He's the son of a popular dem governor so his name is known, but he switched parties a couple of years ago and he's had some image problems with a DUI. I hear he's not running. Jim Douglas, former gov? Not running. Some wealth out of stater? Here's an object lesson for anyone even thinking of carpetbagging here:
Frederick Herman "Fred" Tuttle (July 18, 1919–October 4, 2003) was an American dairy farmer, film actor and one-time candidate for the U.S. Senate from the state of Vermont. He was born in Tunbridge, Vermont, and lived there all his life, except for his service in the United States Army during World War II.
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In 1998 Tuttle was persuaded to run in the Republican US Senate primary. His opponent was Jack McMullen, a multi-millionaire who had lived in Massachusetts for most of his life. McMullen faced opposition from some Vermont Republicans who felt that he was a carpetbagger who apparently moved to Vermont for the sole purpose of establishing residency for a Senate run. The Vermont primary structure allows Democrats and Independents to vote in the Republican primary, and many people foresaw the possibility that Tuttle would beat McMullen by drawing votes across party lines. In addition, some may have hoped that a Tuttle campaign would help to publicize the film Man with a Plan.
The ensuing campaign was remarkable in many ways. Tuttle campaigned on a platform that seemed absurdist by the standards of contemporary politics. McMullen and the state Republican Party challenged Tuttle's ballot petition and got 95 of his signatures invalidated. Tuttle needed 23 more to stay on the ballot and he received 2,309 more signatures. McMullen then gave flowers to Tuttle in the hospital while Tuttle was there for knee surgery.
During the radio-broadcast debate, Tuttle asked a series of humorous local knowledge questions rather than political questions. McMullen was unable to correctly pronounce the names of several Vermont towns, or correctly answer Fred's question "How many teats a Holstein got?," answering "Six", instead of the correct "Four". In the primary, Tuttle defeated McMullen by ten percentage points. Winning the primary with 55 percent of the vote, Tuttle promptly endorsed the incumbent Democrat, Patrick Leahy.
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http://en.wikipedia.org/wiki/Fred_TuttleMan, that was fun.