John Kerry (search) lived two Vietnam experiences -- one as a decorated Navy lieutenant, the other as a staunch protester of the war.

Returning from his tour of duty, the presumptive Democratic presidential nominee testified before the Senate Foreign Relations Committee (search) in 1971, in which he claimed it was U.S. policy in Vietnam to carry out atrocities and war crimes.

A number of Vietnam veterans consider this testimony slanderous and say Kerry had to know it was false. They accuse Kerry of lying about fellow soldiers and officers to push a political agenda, and say his words dishonored comrades in arms at a time of war.

"He knew as an officer that those were lies. It never happened," said Vietnam veteran Carlton Sherwood. "He was principally responsible for cementing the image of Vietnam veterans (search) as drugged-out psychopaths who were totally unrestrained and who were a murderous hoard."

After Kerry's testimony, military and independent investigations found that many of the soldiers who told Kerry and others they committed such atrocities were either never in the service, never in Vietnam or couldn't provide more evidence of those horrific actions.

Kerry told Fox News this weekend that he has no regrets about his service or his protest.

"Now, if some veterans still can't accept that or they don't like the fact that I stood up and spoke my mind, I respect them, that is their choice," Kerry said.

Click here for a complete report by Fox News' Major Garrett.