PORTSMOUTH, N.H. — A senator of New Hampshire, John Sununu, is facing the political fight of his life to retain his Senate seat. Polls in New Hampshire show that the Republican is down at least nine points to his opponent and Democratic candidate for the 2008 U.S. Senate seat, Jeanne Shaheen, who is the state’s former governor.

New Hampshire is important this election season. Mr. Sununu’s seat is a key one for the Democrats to take over in order for their party to reach the 60-member milestone they need in order to gain a filibuster-proof majority. Moreover, New Hampshire, along with Pennsylvania, is a rare northeastern state that is critical to winning the presidency for this election. The Democratic vice presidential candidate, Joe Biden, will campaign in the Granite State tomorrow, and Senator McCain will be here on Sunday.

The election threatens to put a nail in New Hampshire’s reputation as a home to a flinty form of New England Republicanism focusing on individual freedom and low taxes. But in the last four years, New Hampshire’s governor’s office, congressional seats, and both branches of the state legislature have all become Democratic.

For Mr. Sununu, who beat Ms. Shaheen in 2002 U.S. Senate race, the energy coming from the current national Republican ticket of Mr. McCain and Sarah Palin is a lifeline. In an interview with the Sun, Mr. Sununu was quick to embrace Mr. McCain, the winner of the 2000 and 2008 New Hampshire primaries. Mr. Sununu alluded to President Bush once, and only in a negative context to explain his own stance on the Patriot Act.

“John McCain is very popular in New Hampshire. He’s campaigned here many times. He’s always succeeded when he’s campaigned here. People like him. They respond to him. He knows how to campaign in New Hampshire,” Mr. Sununu said after touring the National Passport Center in Portsmouth. “He is always well received and I know Sarah Palin will be as well. They’re an outstanding ticket for New Hampshire.” He called the pair “people who are [as] committed to reform as I am.”

To make his case, Mr. Sununu pointed to legislative achievements with local appeal. He wrote and helped to pass several bills. One bans taxes on Internet service and e-mail, another one protects the nearby White Mountain National Forest, and he passed a law that provides tax credits for the purchase of alternative energy sources, such as wood pellets, which can be used to heat the home. “I’m the youngest member of the senate and yet in my first term I’ve been able to write and pass legislation important to New Hampshire,” he said.

Mr. Sununu faults his opponent for failing to keep taxes low as governor. Ms. Shaheen campaigned on Friday emphasizing energy and environmental concerns. She arrived around 9:30 a.m. at the pastel-colored employee dining room of Stonyfield Yogurt with Senator Tester of Montana in tow. After she and Mr. Tester donned white factory coats, protective eye and footwear, and red hard hats for a tour of the green facility, she made her pitch to Stonyfield’s workers.

Where Mr. Sununu has tailored his message to the concerns of state voters, deemphasizing Mr. Bush, Ms. Shaheen has as well. She shows more openness to energy sources traditionally reviled in Democratic circles, such as oil and nuclear power, all the while attempting to link her opponent and the president.

Asked about drilling by an employee, she said, “I think we do need to increase domestic production. This is an energy challenge and we need to take every opportunity to address that in every way we can.” She added, however, “drilling isn’t the answer long-term.” And on nuclear power, which is a hot button issue in New Hampshire, home to the Seabrook nuclear power plant, for much of Ms. Shaheen’s early career, she seemed now to embrace the plant and the idea of nuclear power.

“I think nuclear does have to be part of the energy mix. I think we’ve seen with Seabrook, once it came online, it’s provided pretty reliable energy,” she said. She cautioned, though, that she opposed subsidizing them: “I think in order for us to make major expansions we need to address the safety issues around disposal of nuclear waste.”

Told about her comments on nuclear power, Mr. Sununu noted that she had served as the campaign manager to a Portsmouth lawyer, Paul McEachern, who ran against his father, Governor Sununu, opposing the Seabrook plant. Ms. Shaheen, in turn, emphasized her ability to work across party lines. “I tried both in my years in politics and as governor to be pragmatic, to try to figure out what we can do to solve people’s problems … and get things done.”

In the coming weeks, voters in New Hampshire will have a hand in determining the fate of both the presidency and the senate.

Mr. Gitell (gitell.com) is a contributing editor of The New York Sun.