Shaheen, who was the state's first elected female governor, is New Hampshire's first Democratic senator since 1975 and the state's first female senator.
"I look forward to working with President Obama to change the direction of this country, to get our economy back on track, to expand affordable health care, to free us from foreign oil and to end this misguided war in Iraq," Shaheen said in her victory speech Tuesday night.
This year's campaign was a hotly contested rematch of the 2002 U.S. Senate race, in which Sununu beat Shaheen by four percentage points. The most recent poll data, conducted on Oct. 31 by the American Research Group, predicted Shaheen's victory by a margin of 53 percent to 41 percent, with six percent of voters still undecided.
David Imamura '10, president of the Dartmouth College Democrats, said he anticipates Shaheen's win will help President-elect Barack Obama implement his policy proposals.
"In order for Barack Obama to be a successful president, he needs a successful team," Imamura said. "Jeanne Shaheen recognizes that we need immediate change in Washington."
The College Democrats' efforts focused primarily on the presidential election, Imamura said, but the organization also campaigned, he added, for Shaheen and U.S. Rep. Paul Hodes '72, D-N.H., who was reelected.
"[Shaheen and Hodes] were facing some of the closest races in the nation and tonight it's great to see that our work is paying off," Imamura said.
At press time, Democrats had increased their majority in the Senate by five seats, with Republican losses in Virginia, North Carolina and New Mexico.
In response to the Democrats' significant gains, Dartmouth College Republicans President Jennifer Bandy '09 stressed the importance of maintaining party checks.
"We need to preserve the right to filibuster in the Senate," Bandy said. "Clearly, Senator Sununu's seat was key for that."
By early Wednesday morning it did not appear as though the Democrats would secure the 60 seats needed to block a filibuster attempts.
The College Republicans focused much of their campaigning this year on the New Hampshire Senate race, Bandy said. She added that "dirty Democratic politics" and tying Sununu to President Bush were both responsible for the Republican loss.
"[Sununu] has done nothing but work for this state -- this is clearly a reflection of the top of the ticket," Bandy said. "It is too bad these days that parties are encouraging straight-ticket voting instead of intellectual choices made race by race."
Ryan Williams, Sununu's communications director, emphasized Sununu's economic experience as a strength during the campaign in an interview with The Dartmouth. Williams cited the millions of dollars spent by Democrats on negative advertisements against Sununu and a country-wide drift away from the Republican Party as factors that contributed to the race's outcome.
"I think the biggest issue that affected us was the national wave against the Republican Party," he said. "[The Shaheen campaign] successfully used their talking points and message to tie us to President [George W.] Bush and his low approval ratings."
According to Williams, Sununu plans to return to the private sector and will also take time off to be with his family, but intends to stay active in public service. Williams said it is too early to tell whether Sununu will run for office in the future. Prior to his term in the Senate, Sununu served three terms in the U.S. House of Representatives.
