The car bombs that killed 51 people on May 11 in a town in southern Turkey are a reckoning for Prime Minister Recep Tayyip Erdogan.

He had made himself party to the fight over Syria and vowed that he would see the end of Bashar Assad's rule. But Assad has hunkered down, and the Turkish leader who called on U.S. President Barack Obama last week faces a dilemma. In the face of Syrian provocations, Erdogan threatens dire consequences, yet draws back, sheltered behind the assertion that his country won't be drawn into a full-scale war with the regime in Damascus.

The bombs in Reyhanli, a quaint border town in the province of Hatay, were just the latest in a series of provocations by Syrian forces. Give Assad credit for his audacity. Like a gambler with steady nerves, he has bet that Erdogan won't pull the trigger.