U.S. soldiers in Vietnam were instructed to fire at anything that moved in designated areas between certain hours. The intent was to cut down Viet Cong movement, but it resulted in the slaughter of peasants who blundered into these "free fire zones."
Lieutenant Kerry participated in free fire zone killing but felt remorse about the innocent lives it cost. He and a group of other officers went to the Admiral to ask that the policy be abandoned or at least mitigated.
Upon his return to civilian life, Kerry denounced free fire zone killing as genocide. In doing so, Kerry admitted being a war criminal. His position has evolved over time, so it's unclear whether he still regards himself as having been a war criminal.
http://hnn.us/articles/printfriendly/3552.htmlBut at its worst, free fire zone killing is small potatoes compared to what Bush has done in Iraq. On his orders, our military has killed so many civilians that we don't even count them.