Three of the House Members who would like to replace John Kerry in the Senate started their busy days Monday glad-handing at the Massachusetts delegation breakfast.

They trained their negative energy on President Bush and showered Kerry — and one another — with effusive praise.

But if Kerry ascends to the presidency, things undoubtedly will change.

At least half, and possibly more, of the Bay State’s 10-member House delegation is expected to jump into a 2005 special election to succeed Kerry in the Senate should he win — and if the Massachusetts Legislature, as expected, changes the way it fills Senate vacancies.

The list of potential candidates is headed by Reps. Marty Meehan and Ed Markey and includes Reps. Barney Frank, Bill Delahunt, Stephen Lynch and John Tierney.

All of them can use the Democratic convention, conveniently located in their backyard, to raise their national profiles and cash.

“It’s a chance to raise your profile — it’s a way to put things in place for a potential race,” Lynch said.

Markey got out to the early lead in the wooing-the-local-party-faithful department by hosting Monday’s delegation breakfast at the Fairmount Copley Plaza Hotel and arranging the speakers.

Besides addressing the delegates himself, he snagged hometown movie star and Democratic activist Ben Affleck, former Rep. Joe Kennedy (D-Mass.), who remains very popular, and Rep. Charlie Rangel (D-N.Y.).

All took the opportunity to bash Bush and build up Kerry.

Kennedy heaped praise on the entire House delegation but his special affinity for Markey was apparent, as he often referred to him as “Eddie.”

Afterwards, Kennedy tamped down rumors that he himself would consider leaving the environmental group he founded, Citizens Energy Corp., to run for Kerry’s seat, saying that “for all intents and purposes” he will not enter the race, if and when it materializes.

“I have no desire to do it; I am not planning on it,” he said.

He was less firm about the possibility of using the $1.7 million that remains in his old House campaign account for a gubernatorial run in 2006 — a race that may attract another Member of the all-male, all-Democratic Massachusetts delegation, Rep. Mike Capuano.

Markey served as a gracious host, welcoming Meehan, who is definitely interested in an open Senate seat, Tierney, who is a strong maybe, and Rep. Jim McGovern, who has expressed no interest.

Today it is Meehan’s turn to star at the daily breakfast.

Meehan and Markey have been the most prodigious fundraisers, each raising more than $1 million in the second quarter of this year, despite the fact that neither is facing a particularly tough re-election bid.

Neither is hosting fundraisers during the convention but two other potential Senate contenders, Frank and Delahunt — who had much more modest second-quarter receipts — each scheduled a big moneymaking event.

PricewaterhouseCoopers hosted a Fenway Park fundraiser on Sunday for Frank, who would become chairman of the powerful Financial Services Committee if Democrats take back the House.

Frank has said that he would not seek an open Senate seat if the Democrats regained control of the House.

In explaining the need for the baseball event, Frank said: “Some of my colleagues have already started campaigning.

“I had hoped we could wait awhile,” he added about the “arms race” for money that has already begun.

Frank planned a fundraising strategy meeting during the convention as well and said he will turn his attention fully to raising money during the August recess.

“I will spend a significant amount of time after the convention on the Senate race,” he said.

Frank began July with almost $280,000 in the bank, compared to Meehan’s almost $3.5 million and Markey’s $2 million.

Delahunt saw an opportunity to entertain his colleagues, show off his district and cash in with a golf tournament and clambake today.

The tournament, to which all House Members were invited, will be held at the Granite Links Golf Club at Quarry Hills in his hometown of Quincy. It’s $2,000 for the whole shebang or 1,000 clams just for the clambake.

Delahunt said he did not plan the fundraiser, or any other event this week, with the Senate race in mind.

“We all hope that we have the opportunity” to run for the Senate, he said, but “our focus ought to be on getting John Kerry elected president.”

Meehan and Markey echoed that sentiment, saying they were not scheduling their events or doing things in Boston with their eyes toward the Senate race.

“There’s been too much chatter about what may happen,” Meehan said. “Getting John Kerry elected should be everyone’s focus.”

Markey’s campaign spokesman also denied that the convention is ground zero for the phantom Senate race.

“He’s not jockeying for anything,” Israel Klein said. “When John Kerry wins the White House, Ed Markey will run for the open Senate seat.”

Lynch, the least senior of the Members interested in Kerry’s Senate seat, was very open about the intertwining of his ambitions and convention schedule.

He said he plans on networking, meeting as many people as possible and talking to delegates and state committee folks.

But Lynch, who only has about $380,000 in the bank, is not hosting any convention fundraisers.

Despite the fact that Lynch is only in his second term and has yet to really crank up the fundraising, Michael Goldman, a Massachusetts-based Democratic consultant, predicted that he could win a potential primary.

Frank, Markey, Meehan and Delahunt could wind up splitting the liberal vote, paving the way for Lynch, a moderate, to win, Goldman said. Robert Keough, editor of CommonWealth Magazine, a Massachusetts political publication, agreed with Goldman’s assessment.

Robert Zelnick, chairman of Boston University’s journalism department, said that Markey and Meehan have fared the best so far in local polls on the hypothetical race.

“Others might be longer shots,” he said, but he was unwilling to rule anyone out.

“I don’t think anybody would be shocked if [Frank] got the nomination,” he said, adding that he is not sure if Frank would be as strong as either Markey or Meehan in a general election.

No discussion about a possible Senate race would be complete without mentioning Republican Gov. Mitt Romney’s role in the scenario.

The Democratic-controlled state Legislature rejected his compromise offer on legislation to strip him of the power to name an interim Senator in the event of a vacancy.

He has threatened to veto the bill requiring a special election to be held in at least 145 days but the lopsided Legislature gives Democrats ample opportunity to override a veto.

Romney has promised not to seek the seat but he continues to be the most-often mentioned Republican name in the mix.

“I don’t think Mitt Romney wants to be a U.S. Senator, even if he has national ambitions,” Zelnick said. “His personality and sense of self is better expressed by a governorship than a U.S. Senate seat,” he said — especially if he is eyeing a 2008 presidential run.

Josh Kurtz contributed to this report.