18-day negotiation yields landmark Iran nuclear accord. After long, fractious negotiations, world powers and Iran struck a historic deal Tuesday to curb Iran’s nuclear program in exchange for billions of dollars in relief from international sanctions — an agreement aimed at averting the threat of a nuclear-armed Iran and another U.S. military intervention in the Middle East. The accord marks a dramatic break from decades of animosity between the United States and Iran, countries that alternatively call each other the “leading state sponsor of terrorism” and the “the Great Satan.” “This deal offers an opportunity to move in a new direction,” President Barack Obama said in early morning remarks from the White House that were carried live on Iranian state television. “We should seize it.” In Tehran, Iranian President Hassan Rouhani said “a new chapter” has begun in his nation’s relations with the world. He maintained that Iran had never sought to build a bomb, an assertion the U.S. and its partners have long disputed. Beyond the hopeful proclamations from the U.S., Iran and other parties to the talks, there is deep skepticism of the deal among U.S. lawmakers and Iranian hardliners. Obama’s most pressing task will be holding off efforts by Congress to levy new sanctions on Iran or block his ability to suspend existing ones.