WASHINGTON—The White House heralded President Barack Obama ‘s phone call with Iranian counterpart Hasan Rouhani earlier this fall as a foreign-policy milestone born of a rush of last-minute diplomacy. But the historic conversation was more intricately choreographed than previously disclosed. Top National Security Council officials began planting the seeds for such an exchange months earlier—holding a series of secret meetings and telephone calls and convening an assortment of Arab monarchs, Iranian exiles and former U.S. diplomats to clandestinely ferry messages between Washington and Tehran, according to current and former U.S., Middle Eastern and European officials briefed on the effort. Mr. Obama had empowered the administration’s top Iran specialist, Puneet Talwar, for some time to have direct meetings and phone conversations with Iranian Foreign Ministry officials, those people say. Some of the contacts took place in Oman’s ancient capital, Muscat, U.S. and Middle Eastern officials say, which sits less than […]