"That Devil Feltman"

After a long and successful career as a U.S. diplomat, AMB Jeff Feltman went on to places where no US official has ever gone before, as the UN's Under Secretary General for Political Affairs. What was it like to meet with Ayatollah Khamenei or Iranian President Ahmadinejad? Or to visit Pyongyang and relay messages from the US president to the North Korean leadership? When is the UN at its most…