WHEN Turkey's prime minister, Recep Tayyip Erdogan, met President Obama at the White House on Thursday, the most pressing topic was the war in Syria. Turkey has not faced a threat on this scale since Stalin demanded territory from the Turks in 1945. In 2011, the Turkish government severed all diplomatic ties with the government of Bashar al Assad and began to support the Syrian opposition groups seeking to oust him. But, thus far, this policy has failed, and it has exposed Turkey to growing risks, most recently two deadly bomb attacks in the Turkish border town of Reyhanli that were most likely planted by pro-Assad forces in retaliation for Turkish support of the Syrian rebels. Turkey's blessing over the past decade has ...