I think Jed Babbin is misquoting General Sherman:
Sherman -- an Indian fighter after the Civil War -- was asked how he could tell a good Indian from a bad one. In a line quoted much less often than his "If nominated I shall not run" line, Sherman said, "kill 'em all and let God sort them out."
This is more or less the line attributed to Arnaud-Armaury, the Abbot of Citeaux, during the Albegensian Crusade (actually I believe the good Abbot said "Kill them all; God will know His own"). Sherman may well have said this, but I thought he was better known for his comment that the only good Indian was a dead Indian, which response actually makes more sense in the context of the question Babbin says was posed to Sherman.
Perhaps Babbin knows better than I, but I can't find any reference to Sherman ever using that phrase. And I know a little more about Sherman than the average hawk.
