Senator Dodd of Connecticut, who announced his candidacy for the presidency yesterday, will attempt to fill a niche as of yet unfilled in the current crop of Democrats: that of the white-maned, Irish American, Northeastern, traditional liberal senator.

Mr. Dodd began his campaign on the “Imus in the Morning” radio program, which is also shown on MSNBC. Domestic priorities were high up in his conversation with Mr. Imus. “It isn’t just Iraq,” Mr. Dodd said. “There are problems here at home that are huge in terms of working people, their jobs, their futures.” Among the issues he targeted were “healthcare, energy policy, environmental questions, education.”

While Senator Kerry of Massachusetts is still mulling a presidential run, Mr. Dodd’s political identity more closely resembles the other Massachusetts senator, Edward Kennedy. A veteran of the Peace Corps and a former general chairman of the Democratic National Committee, Mr. Dodd has served in the Senate since 1981. He is trumpeting his Capitol Hill experience as one of his primary strengths. “I’ve been here 25 years,” he told Don Imus. “Normally that would exclude you from higher office but I think this time around people believe experience matters.”

Mr. Dodd enters the race with a fever pitch of excitement and speculation already surrounding Senator Obama of Illinois and Senator Clinton, and with John Edwards of North Carolina already having announced his candidacy. So the conventional wisdom is that Mr. Dodd is seeking to raise his profile in order to land himself a spot on the Democratic ticket as a vice presidential candidate. If that fails, maybe it would be a cabinet post in a Democratic administration.

By his own admission, Mr. Dodd is less well-known nationally than two of the front-runners for the Democratic nomination, Mrs. Clinton and Mr. Obama. But his congenial personality, that of the consummate political pro, could serve him well in the small living rooms and backyard venues that typify the New Hampshire primary. And the rationale for his candidacy goes: Should either or both of these big-name candidates falter, his nomination could pay off.

Mr. Dodd’s candidacy could have the most impact on the presidential aspirations of Senator Biden of Delaware. Both, after all, are Roman Catholic and from the Northeast. Mr. Biden, however, has a more carefully constructed niche. He will sell his credentials as chairman of the Senate Foreign Relations Committee to argue he has the national security background to lead a nation at war.

“Obama and Hillary are both running a national campaign. They don’t need New Hampshire and Iowa,” said a former Democratic candidate for governor in New Hampshire, Arnie Arneson. “That means that Chris Dodd, Joe Biden, Bill Richardson, all the little munchkins, can have a conversation in Iowa and New Hampshire. This is the perfect place for them to create the relationship and hope that the big guys stumble.”

Mr. Dodd’s term in the Senate is up in 2010. As is the case with many — or even most — American senators, a presidential run has always been part of his plans. He considered, and rejected, running in 2004. The reality of vacant White House makes it a good time for him to take his shot.

“Why not run? What’s he got to lose? There aren’t going to be many more opportunities for him,” said a Democratic strategist, Henry Sheinkopf. Mr. Sheinkopf added that Mr. Dodd would be wise to focus his energies on New Hampshire and Nevada, a “place where blue-collar and people who come from places like Connecticut go because it is a cheaper environment to retire in.”

A veteran of New York politics and former aide to Robert Kennedy, John Moran, is now the vice president of the Red Rock Democratic Club in Clark County, Nevada. “If the election is today, Hillary Clinton is the winner,” said Mr. Moran, noting that Mrs. Clinton’s electoral success in upstate New York indicated she could do well in moderate areas. He added, however, that even less famous presidential candidates could make themselves known in the Las Vegas area, where the population is concentrated.

The first test for Mr. Dodd will be fund-raising. He had the opportunity to get national fundraising contacts as the chairman of the DNC in the 1990s. As the chairman of the Senate Banking Committee, Mr. Dodd is in a key position to raise money from those who work in financial services. He is also close to Democratic fund-raiser and Cambridge, Mass., hotelier Richard Friedman.

“This race is going to cost the winner $60 million,” said a former chairman of the Democratic National Committee, Steve Grossman. “How does he parlay his stature in Connecticut, in the Jewish world, in the financial world, into a fund-raising strategy that gets people to say [after the first quarter], ‘How did he raise x million dollars?'”