Iran and six world powers are closer than ever to a deal that would crimp Tehran's ability to make nuclear arms — a status that would lead to an end to sanctions on the Islamic republic and ease tensions that could boil over into a new Middle East war.
The bad news? Substantial differences remain. A deal by the Nov. 24 target date is unlikely. Both sides may be willing to extend. But that could strengthen opposition in U.S. Congress, triggering a backlash by Iranian hardliners and culminating in the breakup of further negotiations.