Anxious Democrats are scrutinizing a field with as many as three congressmen, two Kennedys, a state senator, and a federal prosecutor as they scramble to find a candidate capable of contending with Scott Brown in the state’s third marquee Senate battle in less than four years.
With Senator John F. Kerry’s nomination Friday to become secretary of state, both parties began in earnest to plan for a special Senate election, probably in middle to late June, with party primaries about five weeks earlier.
Brown, a Republican defeated last month by Democrat Elizabeth Warren, is already seen as the heavyweight in the race, with a strong lead against several potential competitors in a poll taken this week.
But Brown is coming off a loss that stripped away any sense that he is unbeatable. Warren, in turn, will become the state’s senior senator as soon as Kerry departs, a title that highlights how a state known for the clout of its long-tenured senators is now in a period of transition.
Maurice Cunningham, a political scientist at the University of Massachusetts Boston, said Democrats have a built-in edge in any race in the upcoming Senate fight, given their voter registration advantage and robust get-out-the-vote organization.
But the Democratic field, if it is dominated by sitting House members, lacks charismatic candidates who could inspire voters with a grand sense of purpose the way Warren did this year and Brown did in 2010.
“I don’t think it would excite the electorate terribly,” Cunningham said. “They’re what I call ‘It’s my-turn’ candidates.”
Those candidates include US Representatives Stephen F. Lynch of South Boston, Michael E. Capuano of Somerville, and Edward J. Markey of Malden, all of whom have expressed some interest in running.
Before the special election is held, Governor Deval Patrick will have to select an interim senator, who will serve for 145 to 160 days after Kerry vacates the seat.
On Friday, Patrick said he would wait to announce an interim choice until Kerry is confirmed by the Senate, which could happen quickly, given the strong support he appears to enjoy from both parties.
Patrick said he had a “mental list” of potential appointees and has fielded numerous inquiries from people interested in the job. Asked if he was considering a Kennedy, Patrick was coy. “Maybe,” he said.
Potential interim senators include Victoria Kennedy, former senator Edward M. Kennedy’s widow; former governor Michael S. Dukakis; and retiring US Representative Barney Frank. But Patrick said the appointee could come from a broader pool, outside politics.
“I’m looking for a partner,” Patrick said, adding that protecting the state’s federal funding would be a priority for an interim senator.
The governor reiterated that he wants his interim appointee to agree not to run for the seat, arguing it would be difficult for that person to perform official duties while campaigning in a fast-moving election.
He made the same arrangement in 2009, when he selected Paul G. Kirk Jr. to briefly replace Kennedy after the longtime senator died of brain cancer. Brown later surprised the political establishment by winning the seat in a special election early the following year.
In the upcoming election, Patrick said, Brown will not catch Democrats off guard.
“If he runs, he will be a competitive candidate,” Patrick said. “He’s a really good campaigner. But he is, as we have seen, not invincible.”
Brown has hinted strongly that he would like to return to the Senate. His Senate spokeswoman said Friday that he had no immediate comment. Brown’s manager from his recent campaign, Jim Barnett, also had no comment. Brown’s father died Thursday, and the senator is preparing for a funeral on Monday.
If Brown decides against a run, former governor William F. Weld could emerge. He has said he is unlikely to run, but he has not ruled it out.
The Democratic field is less settled, raising the potential for a divisive primary with a fight among several members of the state’s House delegation.
Lynch, a former ironworker, has told labor leaders he is all but certain to run. On Friday, he released a statement saying he would have “big decisions to make” in the coming days.
Capuano, who ran in the 2009 Democratic primary for Senate, is assessing whom he may face in this primary, among other factors, according to two people who have spoken with him. He issued a statement Friday saying he would discuss the race with his family during the holidays.
Markey, the dean of the delegation, has commissioned a private poll to gauge his viability.
US Representative James P. McGovern of Worcester has ruled out a run. “I’d rather stick needles in my eyeballs right now,” he said in an interview last week, citing his family and position on the powerful House Rules Committee.
Some Democrats are longing for a Kennedy whom they believe can excite and unite the party. Edward M. Kennedy Jr., the late senator’s son, is believed to be considering the idea, although he lives in Connecticut.
“He’s looking at it,” said Philip W. Johnston, a former chairman of the Massachusetts Democratic Party. Kennedy did not return messages or e-mails.
Victoria Kennedy may also run, though she is seen as a more likely interim appointee. Through a spokeswoman, she declined to comment.
US Attorney Carmen M. Ortiz said through her spokeswoman that she is not intending to run, but left some wiggle room.
“She has no plans to run for US Senate,” said Christina DiIorio-Sterling. “She thoroughly enjoys her job and . . . intends to fulfill her commitment.”
Attorney General Martha Coakley, who lost to Brown in 2010 but has regained popularity in polls, said she will not run.
State Senator Benjamin B, Downing of Pittsfield was the first potential candidate to comment following Kerry’s nomination Friday. “While there will be no vacancy until Senator Kerry is confirmed, in the next few weeks, I will be meeting with people throughout the Commonwealth as I consider a run for the Senate,” he said in a statement released by a veteran Democratic consultant, Scott Ferson.
In a sign of how far afield Democrats may be casting to find a strong candidate, some are even talking up a run by Ben Affleck, the Hollywood actor raised in Cambridge.
“Well, one never knows,” Affleck said on “Face the Nation,” in an appearance to be broadcast Sunday. “But I’m not going to get into speculation about my political future. I like to be involved, and right now I’m really happy being involved from the outside in government.”