The man left half a leg in Vietnam, won the Medal of Honor, and serve his country for decades as a responsible, principled public servant.
It takes a lot more than a casual reference in a blog to the death of 21 civilians to make Bob Kerrey a war criminal. In fact, even if those deaths occurred, he would be a "war criminal" only if the deaths were intentionally caused, or caused through gross reckelssness, without justification under the circumstances.
Unless you know and have documented far more than you have thus far coyly let on, you should -- at a minimum -- have the basic decency to refrain from appalling slander.
S_A_M
