After WikiLeaks published a trove of U.S. intelligence documents—some of which listed the names and villages of Afghans who had been secretly cooperating with the American military—it didn’t take long for the Taliban to react. A spokesman for the group quickly threatened to “punish” any Afghan listed as having “collaborated” with the U.S. and the Kabul authorities against the growing Taliban insurgency. In recent days, the Taliban has demonstrated how seriously those threats should be considered. Late last week, just four days after the documents were published, death threats began arriving at the homes of key tribal elders in southern Afghanistan. And over the weekend one tribal elder, Khalifa Abdullah, who the Taliban believed had been in close contact with the Americans, was taken from his home in Monar village, in Kandahar province’s embattled Arghandab district, and executed by insurgent gunmen.