Washington and Tehran would need to defend any potential deal as a win for their side. And each has a leader whose approach to talks is vexing mediators.
Related stories
One Nation sets the terms
When to Expect Election Results in Alaska, California, Florida and Wyoming
Exclusive: Cris Cyborg Talks PFL Title Fight, Nunes-Harrison and Post-MMA Plans
Netherlands slams US sanctions on top ICC officials
Steve Sarkisian Put on Notice Amid Texas' National Championship Hype
Billions spent by key federal agency hasn't made American dream of homeownership any easier: report