Massachusetts Sen. John Kerry has long been floated as a potential pick for President Barack Obama’s second secretary of State. The Washington Post recently floated him as in the running for secretary of Defense as well.

Obama would, of course, risk losing one of Massachusetts’ Democratic-held Senate seats in a special election if Kerry joined his cabinet. Nonetheless, Senate Majority Leader Harry Reid, D-Nev., said Wednesday that he would support the nomination of Kerry to a cabinet post and that he was not too concerned about the risk of another special election in Massachusetts.

“I’ll do everything I can to help him if he’s chosen, and we feel very comfortable if in fact something does happen — we feel comfortable in Massachusetts. I think that I’ve already told you how I feel about Scott Brown,” Reid said, in reference to comments made earlier in the news conference about the outgoing GOP senator from Massachusetts.

Brown was elected in a January 2010 special election to fill the Senate seat that became vacant with the death of Democratic Sen. Edward M. Kennedy. He may well make a comeback bid if Kerry gives up his seat.

“I saw during the campaign his plea for bipartisanship. That is a big joke,” Reid said before noting that Brown had chances to side with the Democrats to provide votes to break filibusters and decided against it.

If Kerry does make the move to Foggy Bottom or the Pentagon, who might run to fill out the remainder of his term?

While the world of ambitious Democrats in Massachusetts is large, party insiders believe realistic potential special election contenders include: Rep. Michael E. Capuano, the affable, liberal congressman representing a Boston-anchored district, who ran and lost in the 2010 special election primary; Rep. Stephen F. Lynch, who represents a Boston and south-of-Boston district; State Sen. Ben Downing, who has a base of support of the western part of the state; and City Year co-founder Alan Khazei, who ran in the Democratic primary to take on Brown this cycle, but dropped out after Elizabeth Warren got in the race.

A wealthy, well-connected businessman or businesswoman could also be contender in the sprint that would be a special election primary. Having a personal fortune would be useful, given how short a period of time candidates would have to raise money.

Republican speculation in the blue Bay State makes for a smaller universe of names. Brown tops the list and would begin a special election with near-universal name identification, a fundraising infrastructure and comfortable approval ratings.

Another potential Republican is former Massachusetts Gov. Bill Weld. Longershot potential candidates include: former state Sen. Richard Tisei, who ran and lost against Democratic Rep. John F. Tierney last week, and former Lt. Gov. Kerry Healey.

If a vacancy in representation occurred, Democratic Gov. Deval Patrick would set the date of the special election and appoint an interim senator who would hold the seat until Bay State voters had their say. It’s unclear if that interim senator would also be a candidate to fill out the rest of the term.

Kerry is up for re-election in 2014.