Fall of Raqqa no end game for U.S. as Islamic State, other extremist threats persist, spread

WASHINGTON – The imminent fall of the Islamic State's de facto capital leaves America a multitude of tasks to restore stability in the Middle East, starting with pockets of remaining IS resistance in Syria and Iraq. Then there are the more deeply rooted problems, not fixable by guns or bombs, that allowed extremism to rise and flourish: Syria's civil war and Iraq's intractable political, religious and ethnic disputes, which turned violent again this week. The challenge is more than the U.S. can handle alone. It likely will keep some troops in Iraq for years to come to train and advise the army, police and other members of security forces that imploded when IS fighters swept across the Syrian border and captured Mosul in June 2014. The militants also have footholds in Afghanistan and beyond.