Negotiations with Iran over its disputed nuclear program entered their brinkmanship phase on Friday, with the toughest issues still unresolved a month before the deadline for a final agreement. Iran’s foreign minister, Mohammad Javad Zarif, told reporters covering the talks in Vienna that the moment had come for the United States and its allies to take a “realistic approach” that recognizes Iran will produce significant amounts of nuclear fuel in coming years. The senior American negotiator, Wendy R. Sherman, the undersecretary of state for policy, said she doubted whether “Iran is really ready and willing to take all the steps necessary to assure the world” it has no desire or ability to produce a nuclear weapon. But the two sides showed some indications of progress: Both Mr. Zarif and Ms. Sherman headed home bearing what aides described as a first, tentative draft of a final agreement. The […]