Capuano, a former
Somerville mayor serving his sixth term in the House, positioned
himself as the best candidate to continue Kennedy's legislative legacy,
outlining issues on which he and Kennedy agreed, including his vote
against the war in Iraq and healthcare reform.

"Today I announce
my candidacy for U.S. Senate," Capuano said to a crowd of supporters at
Boston's Omni Parker House Hotel. "I do so extremely humbled by the
achievements of the man in whose shadow we all stand, but also
emboldened by the knowledge that I am the only candidate in this race
who is ready to champion the same progressive ideals that Sen. Kennedy
fought for."

U.S. Rep. Barney Frank, who announced his
endorsement of Capuano at the event, introduced his colleague as an
experienced legislator who will hit the ground "running and kicking and
screaming."

"(Capuano) has a demonstrated record of challenging
the established order," Frank said. "What Michael has is a sustained,
principled irreverence. And I cannot think of anything the United
States Senate needs more at this time."

The list of Democratic
candidates for the seat has grown steadily since former U.S. Rep.
Joseph Kennedy II, Sen. Kennedy's nephew, said he would not run earlier
this month. State Attorney General Martha Coakley and Boston Celtics
co-owner Stephen Pagliuca have both announced they would run. City Year
Co-founder Alan Khazei has said he will announce his campaign next week.

Frank
said that Capuano's experience would win out over the rest of the
field, which also includes Republican State Sen. Scott Brown.

"There
are obviously other people in the Commonwealth who would make perfectly
good Senators," Frank said. "We have an opportunity to get someone who
will be better than perfectly good and who will bring to this job of
the United States Senate precisely what we need at this time."

The
Capuano campaign released the first ad in the race Thursday night, on
Youtube. Among a list of progressive credentials, the 30-second ad
credits Capuano for having "turned Somerville around" during his eight
years as mayor in the 1990s.

Capuano was elected to the House in
1998 to represent Massachusetts' Eighth District, which includes
Somerville, Chelsea, Cambridge and a portion of Boston.

Somerville
Mayor Joseph Curtatone, who attended the announcement, said he is not
considering a run for the House seat should Capuano win the Senate race.

"The
only things I'm thinking about are being mayor off Somerville,
campaigning for Mike Capuano and the [Somerville High School] football
game on Saturday," Curtatone said.

The Jan. 19 special election for the Senate seat will follow a Dec. 8 Democratic primary.