President Donald J. Trump's administration is not known for finesse. But in its December 14 sanctions against Turkey's main defense-procurement entity (the "Presidency of Defense Industries" or SSB) for its purchase of the Russian-made S-400 surface-to-air missile system, it seems to have found a sweet spot: sanctions strong enough to capture Turkish attention but not so sweeping as to shut down bilateral security and arms relations with a NATO ally. The United States seems to be trying to manage a difficult problem, largely of Turkey's making, while...
