A former Marine sergeant facing the first federal civilian prosecution of a military member accused of a war crime says there is much more at stake than his claim of innocence on charges that he killed unarmed detainees in Fallujah, Iraq.

In the view of Jose Luis Nazario Jr., U.S. troops may begin to question whether they will be prosecuted by civilians for doing what their military superiors taught them to do in battle.

Nazario is the first military service member who has completed his duty to be brought to trial under a law that allows the government to prosecute defense contractors, military dependents and those no longer in the military who commit crimes outside the United States.

"They train us, and they expect us to rely back on that training. Then when we use that training, they prosecute us for it?" Nazario said during an interview Saturday with The Associated Press.

"I didn't do anything wrong. I don't think I should be the first tried like this," said Nazario, whose trial begins Tuesday in Riverside, east of Los Angeles.

If Nazario, 28, is convicted of voluntary manslaughter, some predict damaging consequences on the battlefield.