Iran and six world powers have agreed on parameters of a deal meant to block Tehran from developing nuclear weapons. Why is “breakout” time so significant and how is it calculated? WSJ’s Jason Bellini has #TheShortAnswer. Top Obama administration officials entered negotiations with Iran in September 2013 hoping to dismantle most of the country’s nuclear infrastructure—but carrying gnawing doubts such an outcome was possible. Those concerns were quickly confirmed when U.S. and Iranian diplomats sat down for their first formal meeting the following month at the United Nations offices near the shores of Lake Geneva. Iranian negotiators made clear that a dismantling of their facilities, including eliminating tens of thousands of centrifuge machines, a plutonium-producing reactor and an underground fuel-production site, wasn’t feasible, senior U.S. officials said. “It’s our moon shot,” Deputy Foreign Minister Abbas Araghchi told a U.S. official at one point, arguing that the program’s economic and […]