After months of grueling combat, Iraqi troops have finally retaken Mosul, their country’s second-largest city, at the cost of thousands of lives and the destruction of its ancient center. In neighboring Syria, Kurdish and Arab fighters with American advisers are closing in on Islamic State’s capital of Raqqa.
The United States and its allies are winning the major battles. But they are still in danger of losing the war.
The fall of Mosul and Raqqa won’t solve the problem that led to Islamic State’s rise: the misrule of Sunni Muslim areas by governments in Baghdad and Damascus. It won’t even eliminate the terrorist threat that Islamic State poses to the West. Instead, it’ll open a vacuum — and if the Middle East has shown us anything over the past decade, it’s that when there’s a vacuum, bad things can happen.
In the short run, Islamic State still holds big chunks of territory in Syria and Iraq. The group has been displaced from its two biggest cities, and there are persistent reports that its leader, Abu Bakr Baghdadi, is dead. But the rest of its leadership has already moved the de facto headquarters from Raqqa to Deir Ezzor in eastern Syria.