BAGHDAD — An unlikely array of forces is converging on the city of Mosul, lining up for a battle on the historic plains of northern Iraq that is likely to be decisive in the war against the Islamic State group.
The tacit alliance — Iraqi troops alongside Shiite militiamen, Sunni Arab tribesmen, Kurdish fighters and U.S special forces — underscores the importance of this battle. Retaking Mosul, Iraq’s second-largest city, would effectively break the back of the militant group, ending their self-declared “caliphate,” at least in Iraq.