But there has been little outcry in their communities. Settler rabbis and the leaders of American immigrant communities in the West Bank have either played down their crime or offered muted criticism.

It's worth recalling the response of the former prime minister Yitzhak Rabin to another heinous attack two decades ago, when an American-born doctor, Baruch Goldstein, gunned down dozens of Palestinians while they prayed in Hebron.

"He grew in a swamp whose murderous sources are found here, and across the sea; they are foreign to Judaism, they are not ours," thundered Mr. Rabin before the Knesset in February 1994. "You are a foreign implant. You are an errant weed. Sensible Judaism spits you out."