It is increasingly unlikely that six world powers and Iran will meet their July 20 deadline to negotiate a long-term deal for Iran to curb its nuclear program in return for an end to economic sanctions, diplomats and analysts say. In theory, an extension to the high-stakes talks should not be a problem if all sides want it. But President Barack Obama would need to secure Congress’ consent at a time of fraught relations between the administration and lawmakers. Iran, the United States, Britain, France, Germany, Russia and China included the July 20 deadline to reach a comprehensive agreement in an interim deal they reached in Geneva on Nov. 24. The November agreement allowed for a six-month extension if more time was needed for a final deal to end sanctions on Iran and remove the threat of war. An extension would allow up to half […]