ISIS’ brutal, three-year reign in northern Iraq is ending, but the area is at risk of new fighting among ethnic and communal groups, notably over violence under ISIS’ rule, Hamasaeed said. A 2007 peace accord among Sunni and Shia tribes at Mahmoudiya, south of Baghdad, offers a model for the work that may be needed around Mosul following ISIS’ military defeat, the analysts said. The agreement has helped stabilize that region for a decade. The accord was a joint project of a U.S. Army brigade, the U.S. Institute of Peace, a group of trained Iraqi peace facilitators, and local tribal leaders, noted retired Col. Mike Kershaw, who commanded the Army unit, the 2^nd Brigade Combat Team of the 10^th Mountain Division.

Urgency of Mosul, Lessons of Mahmoudiya

To stabilize areas recaptured from ISIS and prevent the group from exploiting a new round of communal fighting to sustain its violent extremist campaign, “Washington must work closely with Baghdad and other allies to prepare a post-liberation political framework for Mosul,” Heritage Foundation analyst James Phillips said.

Mosul after ISIS will be a wrecked city in a humanitarian crisis. The fight has so shattered the warren of buildings and alleys of Mosul’s Old City that “it is often hard to tell the difference between … indoors and outdoors,” Reuters news agency reported. With millions of Iraqis displaced by warfare, notably in refugee camps, extremists such as those of ISIS will target citizens with sectarian attacks and radicalization campaigns, Phillips noted. Those populations must be protected more effectively than has been done in the recent past, he said.

Since the 2007 peace accord at Mahmoudiya, Iraqi mediators have guided similar agreements to prevent local violence in cities including Tikrit and Hawija, Hamasaeed said. Local tribes have agreed to forego traditional responses to conflict that called for blood vengeance or other types of compensation under tribal customs, and instead to use the Iraqi state’s judicial systems to seek justice, he said.

Congressman: Limits of Military Power

Kinzinger, an Air Force combat veteran, joined Kershaw in saying that the United States must not weaken the tools of diplomacy and conflict resolution in its foreign policy and national security toolbox.

“The fact is, the military itself cannot defeat the mindset of radicalism,” said Kinzinger, who serves on the House Foreign Affairs Committee. In the current budget season, those who “say we’ve got to bring down … groups that don’t do military, and plus-up the military alone,” Kinzinger said, are “failing to understand the fact that a bomb is way more expensive than investment in conflict mitigation—for instance, a group like the U.S. Institute of Peace.”

Kershaw noted that, once basic security was achieved at Mahmoudiya, reconciliation transformed what had been one of Iraq’s most violent regions in 2007.

While casualty figures “are somewhat morbid,” he said, “they are a currency in my line of work.” U.S. forces in the Mahmoudiya region had lost about 55 troops killed in action in each of the two years before the reconciliation project—and just one soldier in the year that followed the peace accord, he said.

“In the currency in which I devoted 34 years of my life,” he said, “those were the results that the U.S. Institute of Peace helped us—and … a lot of other U.S. soldiers—achieve.”