A US-led coalition deployed in Iraq more than a decade ago to fight jihadists concluded its mission on Wednesday, a move celebrated by the country’s leaders, but which some fear will embolden pro-Iran armed factions. Coalition troops deployed to Iraq and Syria in 2014 to fight Islamic State, which had seized large swathes of territory, committing massacres and forcing thousands of women and children into slavery. The group was defeated in Iraq in 2017 and in Syria in 2019, but coalition forces...