A final Iranian nuclear deal signed on Tuesday will likely spark a flurry of diplomacy as Europe and Iran seek to repair their dilapidated relations—but true political engagement could prove more elusive. Wariness of Tehran’s ambitions, differences among European Union governments, and the limits of European leverage in a turbulent and fractious Middle East are likely to limit cooperation over issues such as Syria, Yemen or Iraq. First, though, the accord has set off plans for a procession of high-ranking visitors to Tehran. French Foreign Minister Laurent Fabius said Wednesday he will go soon. British Foreign Secretary Philip Hammond on Wednesday said he hopes the U.K. and Iran can fully reopen their respective embassies by year-end. Ties plunged after the 2011 storming of the British embassy in Tehran. European Union foreign policy chief Federica Mogherini, who presided over the nuclear negotiations, also wants to open the first EU mission […]