National Democrats moved swiftly on Friday to close ranks behind Rep. Edward J. Markey as their candidate to run to succeed Massachusetts Sen. John Kerry upon his confirmation as the next secretary of State.

Democratic Senatorial Campaign Committee Chairman Michael Bennet of Colorado released a statement endorsing Markey shortly after Kerry did the same on Friday afternoon.

“Ed Markey always remembers where he came from and will continue the hard work needed to turn our economy around,” Bennet said. “He is exactly the kind of leader Massachusetts needs in the U.S. Senate.”

“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,” Kerry said in a statement.

The Boston Herald is reporting that the late Sen. Edward M. Kennedy’s widow, Vicki Kennedy, is endorsing Markey as well.

Markey announced on Thursday that he would run in the expected special election to replace Kerry. Kerry went on to say that Markey would be “able to hit the ground running on every issue of importance to Massachusetts.”

The move by Democrats to coalesce behind Markey is no doubt aimed at trying to prevent an expensive multi-candidate primary in the special election. Outgoing Sen. Scott P. Brown, who was defeated in November, is considered the leading Republican in the race to replace Kerry.

If he runs, Brown would likely have a clear path to the GOP nomination. Democrats are trying to ensure the same on their side. At least two other members of the Massachusetts delegation have expressed interest in running: Reps. Stephen F. Lynch and Michael E. Capuano.