House Speaker Nancy Pelosi (D-Calif.) formally endorsed U.S. Representative Michael E. Capuano in the U.S. Senate race at the Omni Parker House Hotel in Boston on Friday morning.

Capuano seeks to fill the Senate seat vacated by the death of the late Massachusetts Senator Edward M. Kennedy ’54-’56 in August. This endorsement from the nation’s first female Speaker of the House is an important advantage in the race against opponent Attorney General Martha Coakley who, if elected, would be the eighteenth woman to serve in Congress and the state’s first female U.S. Senator.

Coakley’s campaign has looked to Massachusett’s women in politics, soliciting endorsements from Massachusetts Senate President Therese Murray and US Representative Niki Tsongas. Although Pelosi strongly supports the increased participation of women in government, her public support of Capuano is not necessarily surprising.

“Capuano is a colleague of Pelosi’s and they have worked together for a number of years in Congress, especially in dealing with health care,” said Eric M. Hanzich ’11, political director for the Harvard College Democrats. “Once that was passed, it seemed like a logical step for her to support him.”

The other Democratic candidates in the U.S. Senate race, Alan A. Khazei ’83 and Harvard Business School alumnus Stephen G. Pagliuca, must now determine how to recover from this endorsement.

“The way that you allocate money and the kind of organization that you build is very important,” said Hanzich. “Pagliuca is definitely helped by the amount of money that he has in the campaign.”

“Coakley, as attorney general, benefits from that political machinery,” Hanzich said, adding, “Khazei can find a lot of support from the students here at Harvard. He tries to inspire people through public service and that primary message resonates strongly within the Harvard community.”

Pelosi’s endorsement may also have implications for Republican candidates and members of the GOP.

“I think that it’s an opportunity for Republican candidates to distinguish themselves because there are many people who are unhappy with Washington and disaffected with Pelosi’s leadership,” said Colin J. Motley ’10, president of the Harvard Republican Club.

The primary election will be held on Tuesday, December 8. The special election to replace Kennedy in the US Senate will be on January 19, 2010.