President Trump doubled the tariffs on Turkish steel and aluminum on Friday, causing the Turkish lira to plunge by 16%. The higher tariffs come amid tensions over American pastor Andrew Brunson, who is detained in Turkey, and Turkish cleric Fethullah Gülen, whom the U.S. has refused to extradite from Pennsylvania despite Turkey's allegations of his ties to the failed July 2016 coup.
The big picture: While President Trump himself benefits politically from a trade war with allies, it is actually Russia that stands most to gain from a weakened Turkey. Despite the amicable diplomatic and military coordination between President Erdogan and President Putin in Syria, Russia views Turkey as a geopolitical threat in Eurasia. Russia has attempted to use the Astana peace process to keep its Turkish adversary close, and a widening rift between Washington and Ankara will ultimately redound to Putin's benefit.