Republican incumbent: Susan Collins
Democratic candidate: Tom Allen
Collins, 55, has represented Maine in the U.S. Senate since 1997. She previously held several appointive positions at the state and federal levels. She was the unsuccessful Republican nominee for governor in 1994.
Allen, 63, has been in the U.S. House of Representatives since 1997. Earlier, he had been a city councilman and mayor of Portland, Maine. A previous claim to fame was that he studied at Oxford with fellow Rhodes scholar Bill Clinton.
Polls cited by Real Clear Politics show double-digit leads for Collins.
Collins and her senior colleague Olympia Snowe are among the most centrist Republicans in the Senate. They remain popular in a state that has not voted Republican in a presidential election since 1988.
Here is an article in today's Portland Press Herald regarding an independent TV ad criticizing Allen regarding union issues. I think it gives interesting insight into the politics of that small state.