The death of Abu Bakr al-Baghdadi, leader of Isis, will not have been upsetting to many. But it did serve as a reminder of how much warfare has changed this century. Who gets to decide who is captured and who is killed? What does targeted killing do for the reputations of those who employ the strategy? And does it really protect us from terrorists or is it just old-fashioned vengeance? Andrew Mueller is joined by Lew Lukens, Claire Finkelstein and Lina Khatib.