The negotiations between the United States and Iran to end their war are following President Trump’s familiar playbook for resolving a Middle East crisis: agree to a cease-fire and deal with the toughest problems later. Analysts say the approach has had mixed results in the Gaza Strip, where Mr. Trump brokered a truce last year between Israel and Hamas , the Iranian-backed militant group. Plans for a so-called Phase 2 agreement — under which Hamas was to lay down its arms and Israel would allow