On October 23rd, militants attacked a Turkish aerospace facility near the capital of Ankara. The Turkish government blamed the Kurdistan Workers' Party (PKK)--a Kurdish insurgent group--and launched retaliatory airstrikes. It is very plausible that the PKK is behind this, given the group's history. But the group has also tellingly not claimed responsibility for the attack, and the Turkish government has an incentive to blame the group. Thankfully, terrorism studies scholars have looked into whether and when groups claim attack, and that may give us some insight into what happened here. The...