The agreement, which punted many of the toughest issues to future negotiations, came after a last-minute scramble.

Mediators spent weeks working on a plan to bridge nearly half a century of hostility between Washington and Tehran

By Saad Sayeed, Andrew Mills, Ariba Shahid and Olivia Le PoidevinISLAMABAD, June 18 (Reuters) - Pakistani mediators spent weeks juggling late-night calls and competing drafts…