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The race to be the No. 2 House Democratic leader turned nasty Tuesday, with challenger Rep. John Murtha accusing opponents of "swift-boat style attacks" that hark back to his days being investigated in the FBI's 1980 Abscam sting.

Murtha won endorsement Monday from Nancy Pelosi, who is widely expected to be the House speaker. But Murtha is opposed by some liberals who say they are not happy with the Pennsylvania lawmaker's pro-gun and anti-abortion record. Others say Pelosi took a wrong turn in backing Murtha over her current deputy Rep. Steny Hoyer because Murtha's record is marred by ethics questions of the type Pelosi pledged to clean up in Congress.

"I am disconcerted that some are making headlines by resorting to unfounded allegations that occurred 26 years ago. I thought we were above this type of swift-boating attack. This is not how we restore integrity and civility to the United States Congress," Murtha said of the ample press coverage of his link to Abscam and more recent negotiations he made as ranking Democrat on the Defense Appropriations Committee.

Murtha was not indicted in the bribes-for-political-favors probe and ultimately cleared of wrongdoing by the House ethics committee. But his raunchy language and open-ended option to consider a future deal with undercover FBI agents is forever captured on videotape.

The New York Times on Tuesday also reported that Murtha helped block changes in ethics policies that Democrats proposed last year and is known as "an astute backroom-deal maker known for trading votes for the pet projects known as earmarks. He has had family members who lobbied on issues under his control."

Murtha, a Vietnam veteran who last year proposed a hasty withdrawal of U.S. troops from Iraq, tried to change the subject on Tuesday.

"Of the critical issues we are faced with today, the war in Iraq is the most crucial. The Pelosi-Murtha position on the war is the reason the Democrats are in the majority today. Congressman Hoyer's position has been to stay the course with President Bush from the very beginning and, like Senator John McCain, he advocates sending in more troops," Murtha said.

Hoyer is considered the favorite to win the majority leader race, having visited 82 congressional districts this past election cycle. He helped raise $8.2 million for the party's candidates in the months leading to the Nov. 7 election, earning him letters of support from more than half of the incoming lawmakers who won their seats last week.

After Murtha's statement, Hoyer's office shot back.

"Congressman Hoyer and Congressman Murtha have joined other Democratic leaders from both the House and Senate in signing three letters to the president that outline the consensus among Democrats regarding Iraq," said Stacey Farnen Bernards, Hoyer’s press secretary. "Any representation that Congressman Hoyer endorses a ‘stay-the-course’ strategy or advocates sending more troops to Iraq is wrong."

Murtha's office then responded by paraphrasing a statement issued by Hoyer last year in which Hoyer reportedly said Murtha's withdrawal suggestion would have been disastrous to U.S. national security.

"Since then, Steny Hoyer has chosen not to join 105 of his House colleagues in co-sponsoring Jack Murtha's resolution to redeploy our troops," said Murtha spokesman Andrew Koneschusky. "The record is clear: Jack Murtha has been a constant voice for change in Iraq and Steny Hoyer has not."

At a news conference Tuesday, Hoyer said he still expects to win the post, and despite Pelosi's anticipated endorsement of her friend Murtha, "Nancy Pelosi and I will work very closely together in the future. Why? Because both of us care about the objectives of our party."

Hoyer also has the backing of several members of the Progressive Caucus, who sent a letter Monday to their Democratic colleagues, urging support for Hoyer.

"As our Democratic Whip over the last four years, Steny has worked very well with Nancy and our entire leadership team, and their efforts have helped our caucus achieve greater unity than at any time in the last half century," reads the letter signed by Reps. Maxine Waters, Jerrold Nadler, Elijah Cummings, Jose Serrano, Jesse Jackson Jr. and Emanuel Cleaver.

The group pointed to Hoyer's support for hiking the federal minimum wage, enhancing human and civil rights and environmental protections, increasing education and health care funding and backing the Freedom of Choice Act, which would codify Roe v. Wade.

Three-term Rep. Steve Israel, D-N.Y., said he backs Hoyer, but has not been pressured by Pelosi or others to change his mind and support Murtha instead.

"This is a Democratic Caucus that will be able to develop a consensus, and members will choose whoever they feel would be most representative of our caucus and its principles and values," Israel told FOX News.

Israel added that he doesn't think "the vast majority of the American people woke up this morning" thinking about who's going to be the Democratic leaders in the House. Instead, they are worried about Iraq and other issues, he said.

"I'm focusing my efforts and continuing to try and develop some common-sense, bipartisan solutions to the situation in Iraq, and, frankly, putting the politics and internal Democratic Caucus matters on the back burner where they belong," he said.

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The infighting is not unexpected. Murtha and Pelosi have long been allies, while Pelosi and Hoyer have had a less cordial relationship, starting with her defeat of Hoyer in 2002 to become the minority leader following Dick Gephardt's departure from Congress.

Murtha announced last fall he intended to run for majority leader if Democrats won control of the House, a pre-election jab at Hoyer at a time the Marylander was pledging support for Pelosi.

Pelosi told Murtha to hold back, saying that she didn't want to divide the party while Democrats were trying to win the majority from Republicans after 12 years in the minority.

In her letter Monday, Pelosi began by noting that Murtha had requested her support. Noting his opposition to the war, she added, "Your leadership gave so many Americans, including respected military leaders, the encouragement to voice their own disapproval at a failed policy that weakens our military and makes stability in that region even more difficult to achieve."

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FOX News' Molly Hooper and The Associated Press contributed to this report.