It’s probably no coincidence that Iran’s new interest in regional diplomacy comes as its proxies have faced tougher opposition on the battlefields in Yemen and Syria. In effect, Iran’s Sunni adversaries, led by the Saudis and Emiratis, have decided to push back hard against Iranian-supported forces, by intervening militarily in Yemen and working with Turkey and Jordan to mobilize rebels in Syria. For the first time in many years, Iran seems to be on the back foot in the regional proxy wars.

Rebel gains in northern Syria appear to reflect, in part, a Saudi-Turkish rapprochement that has pumped arms to Islamic fighters in a coalition known as the Army of Conquest. Saudi Arabia has supplied some factions with U.S antitank missiles, even though they fight alongside Jabhat al-Nusra, an al-Qaeda affiliate. Rebel groups in southern Syria are also making gains, and a Syrian opposition spokesman boasted Thursday of a coming “multilayered collapse of regime front lines.”

The United States has been pursuing a two-handed strategy, engaging Iran diplomatically on the nuclear issue while quietly supporting Saudi, Emirati, Jordanian and Turkish military moves.