WASHINGTON (CNN) - House Speaker Nancy Pelosi is weighing in on the battle to succeed the late Sen. Ted Kennedy.
Pelosi is heading to Boston Friday to formally endorse Rep. Mike Capuano in his bid for the Senate.
Capuano, a six-term Democrat who represents the state's 8th Congressional District, is battling Massachusetts Attorney General Martha Coakley, Boston Celts co-owner Steve Pagliuca and Boston businessman Alan Khazei for the Democratic nomination.
"Whether taking on the CEOs of the financial services industry, supporting marriage equality, or voting against the Iraq War because he didn't believe Bush Administration made the case to take military action, Mike Capuano has a proven record of standing up for progressive values and what he believes is right. I am proud to endorse Mike Capuano for U.S. Senate," said Pelosi in a statement.
Capuano is considered a trusted adviser to Pelosi. In late 2006, then Speaker-elect Pelosi tapped Capuano to oversee the Democrats' transition to the majority. The speaker later picked Capuano to head her Special Task Force on Ethics Enforcement.
A new Suffolk University/WHDH survey released Thursday morning suggests that Coakley holds a clear lead in the Democratic race. According to the poll, 44 percent of likely Democratic primary voters back Coakley, with 17 percent supporting Pagliuca, 16 percent supporting Capuano and 3 percent saying they'd vote for Khazei.
The primary is scheduled for December 8 and the general election on January 19th. State Sen. Scott Brown is the only Republican in the contest.
Kennedy died in August. Long time Kennedy adviser and friend Paul Kirk is serving as an interim replacement in the Senate.
Follow Paul Steinhauser on Twitter: @psteinhausercnn