According to an Iranian state media report and an Instagram post under his name, Iranian foreign minister Javad Zarif resigned on Monday. What might have sparked the shock resignation?

Long identified as a key member of the more moderate faction in Iranian politics, Zarif was a key element behind the 2015 nuclear agreement. But with the Trump administration withdrawing from that accord and escalating its diplomatic and intelligence pressure on Iran in other areas, Zarif’s credibility has diminished. Nor has Zarif’s case been helped by the recently hardening European Union stance against Iranian activities on ballistic missile development and terrorist plotting.