The Democratic ranks are closing behind Representative Edward J. Markey of Massachusetts in the race to succeed Senator John Kerry, who hopes to become Secretary of State.
The race is shaping up with unusual speed, considering that Mr. Kerry has not yet vacated the seat, and Gov. Deval Patrick of Massachusetts has yet to set a date for a special election.
But several big guns in the Democratic Party began on Friday to line up behind Mr. Markey, who declared his c andidacy Thursday in a race that was expected to be crowded with wanna-bes.
The first to issue a statement was Mr. Kerry.
“While I began last week to formally step out of politics and it's very important that I respect the apolitical nature of the post I hope to soon occupy, as Massachusetts' senior senator today and as a colleague of Ed Markey's for 28 years, I'm excited to learn of and support his decision to run for the United States Senate,'' the statement said.
It avoided the word “endorse†but was clearly intended to send a signal that Mr. Kerry was supporting Mr. Markey.
Victoria Reggie Kennedy, the widow of Senator Edward M. Kennedy, then endorsed Mr. Markey, saying in a statement, “He knows how to get things done.â€
Mrs. Kennedy is said to be interested in being appointed interim Senator until the winner of the special election is declared, but she did not mention this in her statement.
Her s tatement was followed by one from Senator Michael Bennet, chairman of the Democratic Senatorial Campaign Committee, in favor of Mr. Markey.
“At a time when the country needs real leadership that looks out for the middle class, Ed Markey always remembers where he came from and will continue the hard work needed to turn our economy around,†Mr. Bennet wrote.
Mr. Markey, 66, is the dean of the Massachusetts Congressional delegation and was first elected to the House in 1976. The other most likely candidates are also members of Congress: Stephen Lynch and Michael Capuano.
The Democrats appear to be trying to head off a potentially bruising primary and save their money for the special election. Their most likely Republican opponent is Massachusetts' other outgoing senator, Scott Brown.
Mr. Brown, who lost his seat last month to Elizabeth Warren, has not said yet whether he intends to run again this time. But he is presumed to be a formidable candidate; he is certainly the best known in the field, now that a couple of high-profile Democrats have said they are not interested. They include Edward M. Kennedy Jr., the late Senator's son, and Ben Affleck, the actor.
Representative Niki Tsongas, the widow of another senator, has also said that she will not run. So has Martha Coakley, the state attorney general, who lost a special election to Mr. Brown in 2010.
Mr. Markey, the son of a milkman, has $3 million in his campaign account. He ranks ninth in seniority in the House.
Follow Katharine Q. Seelye on Twitter at @kseelye.