Senate seats don’t open up too often in Massachusetts, so one can forgive Bay State pols for coveting Sen. John Kerry’s (D) long before he’s won the Democratic presidential nomination, let alone the presidency.

But the dream became a little more real following Kerry’s surprise victory in Monday’s Iowa caucuses and his surge in the New Hampshire primary polls.

The list of possible successors is long and distinguished, but anyone who’s willing to vault ahead to a John Kerry presidency must first discuss temporary stewards.

Massachusetts Gov. Mitt Romney (R) would appoint President Kerry’s successor and he would, presumably, name the state’s first Republican Senator since 1978. That person would then face the electorate in a special election in 2006.

The person most likely to succeed, according to Democratic operatives is … Mitt Romney.

“There’s speculation that the governor could appoint himself,” said Mary Lane, communications director for the Massachusetts Democratic Party. “He’s a man with national ambitions and the Senate could widen his appeal.”

But Lane added that Romney may have even higher aspirations — presidential ones — in which case he may not want to appoint himself in order to run for commander in chief in 2008, assuming he is re-elected in 2006.

There is also potential political peril for a governor who appoints himself to the Senate. After then-Minnesota Sen. Walter Mondale (D) was elected vice president in 1976, Gov. Wendell Anderson (D) resigned so his successor could appoint him to the Senate. Anderson then lost a bid for a full term in 1978.

Another name being mentioned for a Senate vacancy is former Suffolk County District Attorney Ralph Martin (R), Lane said.

“He’s immensely popular … and has wide appeal … he would be a very formidable candidate,” she said. “He’s a moderate Republican who many consider to be a conservative Democrat.”

For good measure Lane added the obligatory disclaimer that all such talk is just conjecture at this point.

Romney and Martin also top other Democratic insiders’ lists.

GOP operatives see things a bit differently.

On a possible Romney appointment, one says, “Been there, done that,” referring to Romney’s 1994 attempt to unseat Sen. Edward Kennedy (D).

Romney posted a respectable 41 percent against the “liberal lion” but is not likely to go that route again, the source said.

More likely Romney would tap Martin or White House Chief of Staff Andrew Card, the source continued. Other good bets would be his lieutenant governor, Kerry Healey, or Boston attorney Gloria Larson. Either would be the only woman in the Massachusetts delegation.

And not to be forgotten is former Gov. Paul Cellucci (R), who is currently the ambassador to Canada, the source added.

Other GOP contenders include national Log Cabin Republican Executive Director Patrick Guerriero and Massachusetts Republican Party Chairman Darrell Crate.

Whomever Romney would appoint would face a litany of big-name Democratic challengers in the 2006 special to fill the remaining two years of Kerry’s term.

That election would coincide with a race for Kennedy’s seat. The veteran Senator — who was elected to fill the remainder of his brother John F. Kennedy’s term in 1962 after JFK became president — has not said whether he plans to run again in 2006, when he will be 74 years old.

A good chunk of the Massachusetts Congressional delegation — all Democrats — would likely line up for the Kerry seat, insiders say.

Topping the list of Senate wannabes are Reps. Marty Meehan, Ed Markey and Barney Frank.

“A few of the Congressmen would eye that seat,” Lane said.

Only Frank has discussed the idea publicly so far.

“I have been asked if there were a Senate vacancy, if I would run, and yeah I would,” Frank recently told Bay Windows, an alternative New England newspaper.

Meehan and Markey are said to be equally, if less visibly, interested.

For his part, Kerry is staying out of the fray.

“Right now, Senator Kerry is focused on winning the nomination and not anything else,” a campaign spokesman said.

In a prepared statement to Bay Windows, the possible Democratic White House frontrunner went considerably further.

“I think Barney Frank is focused right now on holding the House Republicans in line and I’ve got to beat President Bush before there’s any talk of a Senate seat vacancy in Massachusetts,” Kerry said. “But that doesn’t change the reasons why you’re talking about Barney’s future. He’s a remarkable public servant and he’s done so much for Massachusetts and the nation. He’s smart as hell; he’s tenacious; he’s witty and he’s a fighter.

“Barney speaks his mind and argues his case better than just about anyone. Just ask Dick Armey,” Kerry finished, in reference to the former House Majority Leader who once accidentally called the openly gay Frank “Barney Fag.”

All three Democratic Members most frequently mentioned for the vacancy have served in the House for years.

Meehan has the fewest under his belt, having first been elected in 1992, followed by Frank, who has 20-plus years in the House, and then Markey, who has served since 1976.

None would speak on the record for this article, however.

Both Frank and Markey said through spokesmen that it would be inappropriate to speculate so early in the presidential contest.

“Congressman Markey refuses to engage in speculation about a hypothetical Senate race at this time,” Markey spokesman Israel Klein said. “There will be plenty of time to discuss that at President Kerry’s inaugural ball,” he added.

As for other Democratic contenders, one insider said Rep. Mike Capuano, with his large Boston base, could be “surprisingly strong,” as could Rep. Bill Delahunt, though his Cape Cod district makes it harder for him to run statewide, the source said.

A final possibility is state Attorney General Tom Reilly, who the Boston Globe reports “has built up a $1.3 million war chest as he contemplates running for governor.”

Then again, a gubernatorial bid could become a Senatorial bid if the political environment is right, knowledgeable sources say.