The United States has urged Mr. Erdogan to halt his attacks on the Syrian Kurds, who now control most of the 565-mile boundary with Turkey and may soon seize the last section of territory that would give them a contiguous region. American officials say the Turks agreed to a pause in the fighting negotiated by the United States and Russia that takes effect Saturday.

At the same time, Washington has asked the Syrian Kurds to resist taking advantage of the chaos of war to seize more land. An effort on their part to claim that final patch of territory along the border could provoke Mr. Erdogan to come down even harder with military force. One worry is that Russia, which is also courting Kurdish allegiance by providing air cover for their operations, would then retaliate against Turkey on behalf of the Kurds. President Vladimir Putin of Russia may indeed be looking for an excuse to pay Turkey back for shooting down a Russian jet that strayed into Turkish airspace in November, but Mr. Erdogan should resist giving him an excuse to do so.

Mr. Erdogan’s problems with the Kurds are largely of his own making. He had in fact made some headway in peace talks with Kurdish leaders in Turkey before resuming hostilities last year. He should seek ways to revive that process. As for the Kurds in Syria, he should stop shelling them and instead work with the United States to find a way to accommodate what could eventually become an autonomous Kurdish region in Syria. Mr. Erdogan has found a way to work with the Kurds in Iraq. Fighting Syrian Kurds and inflaming tensions with America makes no sense.