I heard it said about the thousandth time in the last six months, "I'm just against war and violence."
I finally, rather calmly said, "I'm not. If the only way that you can stop a rape or a murder is through a violent act. I'm all for it. If the only way that you can stop a genocide is by declaring war, I'm for it. I'm against aggression. "
That actuality got the other dude to change his tune fairly quickly.