Sununu is seen as vulnerable, and Democrats are hoping a grueling rematch with Gov. Jeanne Shaheen will be successful and help the party extend its current two-seat U.S. Senate majority, The New York Times reported Monday.
But, analysts warn, Sununu will present a formidable challenge, citing his youth -- he's 43 -- and $5.1 million campaign war chest. Shaheen, 61, was the state's first female governor when elected in 1996.
She was defeated by Sununu in 2002, but since then, state Republicans have lost an 11-point edge in party identification. President George Bush is highly unpopular, making it tough for the GOP, the newspaper said.
"It's probably the best test out there of a political climate being a Republican incumbent's worst enemy," Jennifer Duffy of the Cook Political Report told the Times. "(Sununu) does constituent service. He shows up to work. He votes. He brings home the bacon. There are not a lot of inherent things wrong with John Sununu except that he is a Republican."