Massachusetts Democratic Rep. Niki Tsongas, broke ranks with the men in her House delegation, endorsing state Attorney General Martha Coakley in the special Senate election.

Tsongas, who herself went to Congress via a special election in 2007, touted Coakley's record as attorney general and service to the state. "I am proud to endorse Martha Coakley for U.S. Senate because she will be that thoughtful, innovative, effective leader Massachusetts urgently needs," she said in a statement.

In backing the attorney general, Tsongas passed over her House colleague, six-term Rep. Michael E. Capuano who is one of three men running against Coakley in the Dec. 8 Democratic primary. Four other Massachusetts House members have endorsed Capuano: Democratic Reps. Jim McGovern, Barney Frank, John F. Tierney and Stephen F. Lynch.

Massachusetts Rep. Stephen F. Lynch unexpectedly took himself out of consideration for the Democrats' Senate special election nomination Tuesday, shaking up the race just as it looked like the field for the Dec. 8 primary was solidifying.

In a short statement, Lynch said he concluded that "the challenge of putting together the resources and organization necessary to wage a competitive statewide campaign in less than 90 days is insurmountable." Observers have estimated it will cost between $3 and $5 million to fund a competitive campaign.

The move was a surprise, as Lynch appeared poised to launch his bid in the primary to choose the Democratic nominee for the Jan. 19 special election, which will fill the seat left vacant by the Aug. 25 death of Democratic Sen. Edward M. Kennedy. Lynch had been widely expected to run as a more moderate alternative to other, more liberal Democrats in the race.

Lynch -- who has represented the Boston-based 9th Congressional District since 2001 --obtained nomination papers from the office of Massachusetts' secretary of state Sept. 4. And he filed paperwork to form a campaign committee, Stephen F. Lynch for Senate, on Friday.

Massachusetts Rep. John Tierney, a favorite of the House Democratic leadership, has decided against running in the special election for the Senate seat left vacant by the Aug. 25 death of Democrat Edward M. Kennedy.

"A great number of people have kindly urged me to run for the United States Senate," Tierney said in a statement released Monday morning. "I have given the matter serious consideration and determined that, at this time, I can best be of service in the U.S. House of Representatives -- continuing to work to make education more affordable and accessible, to build and strengthen our nation's workforce, to enact meaningful health care reform and to ensure we have a pragmatic foreign policy."

He continued, "These and other serious matters must be addressed in the coming weeks and months and they, along with my constituents, warrant my full attention."

Democrat Elizabeth Roberts, the lieutenant governor of Rhode Island, has decided to forgo the 2010 bid for governor that she had been mulling. Roberts will instead seek re-election to her current post.

"I want to thank all of my supporters and let them know that I will continue to work to turn the pages of politics as usual in Rhode Island," said Roberts in a statement released Wednesday afternoon. "I will continue to fight for quality health care for all; a stronger, more diverse Rhode Island economy; and honest, open and effective government."

Roberts, by choosing to pass up the race to succeed term-limited Republican Gov. Donald L. Carcieri, thins a primary field that looked crowded with prominent Democratic officeholders. Rhode Island Attorney General Patrick Lynch and state Treasurer Frank Caprio are both expected to launch campaigns for the open seat.