Russia’s use of an Iranian air base to bomb targets in Syria sends a message to Washington as it weighs a military partnership with Moscow: Join us or we’ll look to your enemies. Tuesday’s missions were unprecedented. Iran allowed Russian warplanes to take off from its territory to strike opposition targets in Syria. The move came with little notice to the

United States, which has watched helplessly the escalating bloodshed near Aleppo, the country’s biggest city, and even offered an alliance with Russia against Islamic State and other extremist fighters as a way to get Syria’s government out of the fight. The negotiations have dragged on for weeks. Russia has grown impatient, with top officials several times suggesting an imminent deal, only to have American officials counter that the sides weren’t close. CONTINUE