Are We Winning the War Against ISIS?

• Author: Zissou, Rebecca
• Position: INTERNATIONAL

The U.S. and its allies have driven the terrorist group from much of its territory. But truly defeating it is a lot more complicated.

When Iraqi forces finally retook Mosul, Iraq's second-largest city, from the terrorist group ISIS this summer after a nine-month battle, they came upon scenes of horrible carnage.

The fighting had reduced buildings to rubble, streets were littered with the burnt-out remains of cars and strewn with dead bodies, and the city's liberators found starving families who'd huddled for weeks in basements to escape the gunfire.

ISIS (the Islamic State of Iraq and Syria) had controlled the city since 2014, subjecting residents to its brutal rule and punishing opponents with torture or death. The battle to push ISIS out of Mosul killed more than 40,000 civilians and forced nearly a million others to flee.

The fall of the city to Iraqi troops supported by the United States was a major blow to ISIS--and the latest in a string of defeats for the radical Islamist group. Experts say ISIS has lost about 60 percent of its territory since January 2015, from an estimated 35,000 square miles to 14,000 square miles today (see map, p. 16). In recent months, the U.S. and its allies have also killed top ISIS leaders, reduced the number of ISIS fighters, and cut off much of its oil supply--a major source of income.

"These are obviously major blows to ISIS," says Hassan Hassan of the Tahrir Institute for Middle East Policy in Washington, D.C. But "its leadership and its ability to grow back are still there."

Indeed, experts warn that the fight against ISIS is far from complete. The organization continues to attract followers, carry out terrorist attacks in the region and beyond, and inspire extremists around the world to kill innocent people in ISIS's name.

The Rise of ISIS

ISIS traces its roots to one of the radical groups that emerged in Iraq during the violent years that followed the 2003 American invasion. The group merged with other extremist groups in Syria to form what is now known as ISIS. Its goal from the beginning has been to re-establish a state ruled by strict Islamic law, known as a caliphate, like the ones that dominated the Middle East in past centuries. It also aims to destroy the West.

The group's followers, Sunni Muslims, are engaged in a bitter rivalry with members of Islam's other major sect, the Shiites. (That's why ISIS sees the Shiite-led governments of Iraq and Syria as enemies.)

When Syria erupted into a civil...