In a widely anticipated move that will set up a race to watch in November, New Hampshire's Democratic Gov. Jeanne Shaheen officially entered the race for Senate Wednesday.

"I want to let the people of New Hampshire know I do intend to seek the seat in the U.S. Senate," Shaheen said. "The people of this state need a champion who is going to work for them in Washington."

Shaheen's decision to run for the seat held by Republican Bob Smith ends more than a year of speculation girded by an August announced establishing an exploratory committee.

The Democrats hold a one-vote edge in the Senate and control of the Senate rests in a handful of races. Republicans are running for re-election in 20 seats, Democrats are seeking to keep 14.

"New Hampshire is the most likely chance the Democrats have to gain a Republican seat," said New Hampshire Democratic Party communications director Colin Van Ostern.

Van Ostern said the race is sure to be a nail-biter, one he doesn't want to underestimate since the Republican candidate will be well-funded and there are more Republicans in the state. Bush won the presidential election there in 2000, and currently Shaheen is the only Democrat of five statewide officials.

But Van Ostern said three-term Gov. Shaheen, who has no primary competition, could be a history-making candidate. The first female governor may become the first female senator for the state, and Van Ostern said possibly the first female in U.S. history to be both a governor and a senator.

But she must first battle the Republican nominee, a race that is experiencing its own first. Seated Sen. Smith is being challenged by three-term Rep. John E. Sununu, the son of former White House Chief of Staff and New Hampshire Gov. John Sununu.

Smith, in his second term, lost a lot of Republican support in the state and among Senate colleagues when he briefly quit the party in 1999 and delivered a scathing speech to the Senate. He returned to the party after a failed bid for the presidency. Now, he is facing an unexpected challenge from within his delegation.

In recent polls, Smith and Shaheen are in a dead heat, but Sununu has been polling better than Shaheen even more recently.

And illustrating the importance of New Hampshire to the presidential race, Shaheen has received money and staff pledges from the entire field of Democratic White House hopefuls.

Sens. Tom Daschle of South Dakota, John Edwards of North Carolina, Joe Lieberman of Connecticut, John Kerry of Massachusetts, Rep. Dick Gephardt of Missouri, and former Vice President Al Gore have all offered top personnel and PAC contributions to Shaheen's candidacy.

Van Ostern said Shaheen has received a lot of support from national Democratic leaders, but that support is two-fold. One, she is a likely candidate to pick up the seat, and two, all the candidates will be in New Hampshire for the 2004 races. 

"Jeanne Shaheen has always been a significant political power in New Hampshire," he said, adding that Democratic leaders regularly make stops in the state.

But Democratic leaders no doubt have decided they would like to do all they can to win Shaheen's favor and insert their operatives into her organization for future use.

And if she wins, it will prolong a streak. Asked why she decided to run, Shaheen joked, "Hey, the [New England] Patriots won the Super Bowl — I'm feeling lucky."

Shaheen said two of her priorities in the Senate would be lowering the cost of prescription drugs and protecting the environment.

"One of the things I've learned as governor is sometimes, in order to makes things happen for people in New Hampshire, you need to change policies in Washington," she said.

Fox News' Carl Cameron and The Associated Press contributed to this report.