By Emily Cadei, CQ Staff

Scott P. Brown, one of the handful of Republicans in the Massachusetts Senate, announced Saturday afternoon that he is a candidate for the state’s vacant U.S. Senate seat. And his bid for the GOP nomination received a boost late Friday night when Andrew Card — former chief of staff to President George W. Bush — revealed that he will not run in the upcoming special election to replace the late Democratic Sen. Edward M. Kennedy .

Brown, speaking at the Omni Parker Hotel in Boston, acknowledged the long odds he faces in strongly Democratic Massachusetts. But he said that the Democrats’ dominance in the state is itself an argument for his candidacy.

“Does Massachusetts need another elected official to merely rubber-stamp the policies of one party or administration?” Brown asked. “Massachusetts needs someone who is an independent thinker, who does not take his or her orders from the Washington insiders, or from Harry Reid or Deval Patrick .” Reid, a Nevada Democrat, is the Senate majority leader from Nevada, and Patrick is the Democratic governor of Massachusetts.

Brown is in his third term in the state Senate — a 40-member body in which he is one of five Republicans — after serving three terms in the Massachusetts House. Still, he signaled he will run as an outsider. “I am not part of the Beacon Hill insider club,” he declared, referring to the location of the state Capitol in Boston. He pledged to bring fiscally conservative principles to the Senate.

Brown is the first Republican to officially launch a campaign to succeed Kennedy, the longtime Massachusetts political icon who died of brain cancer Aug. 25. He will likely have the backing of most of the state’s GOP establishment, especially since Card and former Lt. Gov. Kerry Healey, the two biggest names mentioned as possible Senate contenders, have decided to pass on the race.

Card threw his support behind Brown in a statement sent out by the Massachusetts Republican Party Friday night. He said he was “heartened and grateful” for the outpouring of support he had received for a potential Senate bid. “But ultimately, the decision is what I believe to be in the best interest of my family,” he said. “Now is not the right time for me to enter a political race.”

Card would have given the Republicans a high-profile candidate with the national fundraising ties. He began his public career by serving eight years in the Massachusetts House, leaving his state legislative seat open in 1982 when he ran a failed bid in the Republican primary for governor. He then served as a top aide to President George H.W. Bush before taking over as secretary of Transportation in 1992 near the end of the elder Bush’s one term.

But any Republican candidate can expect an uphill battle to win the Jan. 19 special election to succeed Kennedy in Democratic-dominated Massachusetts. And Card would have brought additional heavy baggage into the race because of his close ties to President George W. Bush , under whom he served as chief of staff from 2001 to 2006. Bush was rejected soundly by Massachusetts voters in both his 2000 and 2004 presidential races, and he remains widely unpopular in the state.

The odds favoring a Democratic victory are drawing a much larger and higher-profile field into that party’s Dec. 8 primary. State Attorney General Martha Coakley is already in the Democratic contest and has obtained the backing of the fundraising juggernaut EMILY’s List, a political action committee that supports Democratic women candidates who favor abortion rights. Several other Democrats, including Reps. Michael E. Capuano and Stephen F. Lynch , are expected to jump in the race.

But Rep. Edward J. Markey , the dean of the 10-member, all-Democratic Massachusetts U.S. House delegation, announced Friday afternoon that he would not seek the seat, citing his seniority in the House. Markey, who was first elected to the House in 1976, currently chairs the Energy and Commerce Subcommittee on Energy and Environment and the Select Committee on Energy Independence and Global Warming.

First posted Sept. 12, 2009 12:13 p.m.