Long, fraught timeline of tensions over Iran nuclear program

FILE - U.S. Secretary of State John Kerry, right, during official talks with Iranian Foreign Minister Mohammad Javad Zarif, left, in Geneva, Switzerland, May 30, 2015. A framework nuclear deal is announced in April 2015 — after months of negotiations, outlining long-term restrictions on Iran’s nuclear program and the removal of many international sanctions. (AP Photo/Susan Walsh, Pool, File)

Long, fraught timeline of tensions over Iran nuclear program