(CBS) Democrat John Murtha is one of Congress's most vocal opponents of the war in Iraq, but the former Marine's own war record is now coming under fire from a familiar source.

CBS News correspondent Sharyn Alfonsi reports from deep in the heart of Pennsylvania steel country that Rep. Murtha is engaged in a new battle this one in his own backyard.

This is what Murtha, a Vietnam veteran, is saying: "I don't appreciate these people sitting on their fat backsides at the White House, sending our young people to war when they don't understand the circumstances."

But this is what he's facing: "We are her to 'Swift Boat' John Murtha."

That's right, "Swift Boat." Veterans for Truth some of the same guys that went after John Kerry's military record in 2004 is back.

This time, they are gunning for Murtha who is up for re-election by questioning his military record and his character.

"Our campaign is entirely negative, but as we all know, negativism is a positive aspect of American politics," said fellow Vietnam vet and former Congressman Don Bailey.

This weekend, they organized a "Boot Murtha" rally.

Murtha, ever the Marine rolled out some heavy political ground support of his own to take them on.

"Jack Murtha's critics don't know Jack," said fellow Vietnam vet and former Senator Bob Kerrey.

"This guy laid his life on the line for us and for our country, and we're not going to let any Swift Boaters, shrimp boaters or anybody else take out Jack Murtha," said another Vietnam vet and the former Supreme Allied Commander of NATO.

No one thought the 16-term Congressman was in any danger of losing his seat to Diana Irey - his "stay the course" Republican challenger. But the "Swift Boat" guys changed the equation, so Democrats are changing their battle plan.

"Take your dirty politics, shove it where the sun doesn't shine and leave town," is how former Senator and Vietnam vet Max Cleland put it.