Murtha moved back to Johnstown and remained with the Marine Reserves until he volunteered to go to Vietnam. He served as an intelligence officer there from 1966 to 1967 and received a Bronze Star and two Purple Hearts.

After his discharge from the Marines, Murtha ran a small business in Johnstown. He went to the University of Pittsburgh on the GI Bill of rights, graduating in 1962 with a degree in economics.

He served in the Pennsylvania House in Harrisburg from 1969 until he was elected to Congress in a special election in 1974. In 1990, he retired from the Marine Reserves as a colonel. "Ever since I was a young boy, I had two goals in life -- I wanted to be a colonel in the Marine Corps and a member of Congress," Murtha wrote in his 2004 book, "From Vietnam to 9/11."

Murtha's criticism of the Iraq war intensified in 2006, when he accused Marines of murdering Iraqi civilians "in cold blood" at Haditha, Iraq, after one Marine died and two were wounded by a roadside bomb.

Critics said Murtha unfairly held the Marines responsible before an investigation was concluded and fueled enemy retaliation. He said the war couldn't be won militarily and such incidents dimmed the prospect for a political solution. "This is the kind of war you have to win the hearts and minds of the people," Murtha said. "And we're set back every time something like this happens."