But thats the problem. You and I see the difference; the writer is the one who equated them. According to his distinctions, a German citizen could not morally cooperate with the Americans to overthrow Hitler nor could he act against Hitler on his own. I'm not sure thats what he would mean to say had he thought it through.
The whole issue of "just war" is seldom going to be entirely clear cut, and in any conflict you'll find good people in disagreement with one another as to what is right and proper, but this writer hasn't attempted to draw the necessary distinctions. He has I think falsely equated the two cases.
One of the problems as I see it, is in leaving to the individual the decision of who needs to be murdered because their acts are so heinous, and assuming that God is speaking to any individual and telling him or her to commit murder.
I said on a previous thread that I don't believe that God tells any of us to commit sin. It is clear in God's word that we are not to murder, and Jesus goes even farther and tells us not even to hate. There is no situation where Jesus tells anyone to murder anyone else (and He was dealing with Pharisees and brutal Romans, as well as Herod Antipas). I think we can see from Jesus' words and from His example that murdering another is sin, and therefore, Roeder's murder of Tiller, no matter how good the results, is still sin.