Concerns Grow as U.S. Withdraws from Iraq While ISIS Rebuilds

As the U.S. readies itself to leave Iraq entirely, experts warn that the Islamic State group (ISIS) is quietly regrouping, potentially ready to take advantage of the security gap left behind. U.S. forces are scheduled to finish their withdrawal by September 30, raising alarms about the already precarious situation in Iraq.

Iraq’s struggle to control Iranian-backed militias could lead to one of the most volatile periods the country has seen since ISIS’s capture of Mosul in 2014, according to counterterrorism specialist Dr. Omar Mohammed. “ISIS is just biding its time, waiting for the right moment,” he commented, highlighting the group’s historical patterns of exploiting instability.

In fact, the current dynamics in Iraq suggest that as militias portray ISIS as a looming threat, the terrorist organization is capitalizing on dissatisfaction generated by these same militias. “This is really the cycle we saw lead up to the fall of Mosul,” Mohammed noted.

Back then, ISIS seized Mosul after a long period of preparation, and the city’s defenses crumbled. The group had set up a covert infrastructure through activities like extortion and infiltration, eventually capturing a vast amount of American-made weapons and resources. Mohammed had started a blog, “Mosul Eye,” during that time, which documented life under ISIS, revealing their operations to U.S. forces.

Despite the territorial losses ISIS sustained, the organization still remains active in certain areas of Iraq and Syria. U.S. Central Command (CENTCOM) has stated it will continue efforts to disrupt ISIS’s resurgence. However, some analysts believe that since recent regime changes in Syria, the number of ISIS fighters there has skyrocketed, raising new alarm bells.

Simultaneously, the Popular Mobilization Forces (PMF)—an organized group within Iraq’s security framework—has not disbanded even after ISIS’s territorial defeat, retaining close ties to Iran. Estimates suggest that the PMF is composed of around 238,000 members, and receives substantial government funding.

Baghdad is currently focused on integrating armed groups such as Kataib Hezbollah fully under state control. The timeline ahead is not just about the U.S. withdrawal—it’s also about disarming militias, a process that isn’t straightforward. “Both ISIS and these militias depend on each other for legitimacy,” Mohammed argued.

Meanwhile, U.S. actions are closely aligned with a broader agreement which outlines a complete withdrawal by 2025, though operations against ISIS in Syria will continue into 2026. Mohammed suggests that repeating the mistakes of the past would be disastrous. “Mosul fell not simply because of ISIS’s strength, but because the focus shifted away from the reality on the ground,” he emphasized.

Iraqi Prime Minister Ali al-Zaidi recently met with U.S. officials to discuss the ongoing troop withdrawals, which didn’t sit well with Tehran. Iranian advisor Ali Akbar Velayati termed the meeting “regrettable,” underlining the enduring tensions.

Mohammed pointed out that with the fallout from U.S. airstrikes affecting Iran’s proxy networks, the situation in Iraq has never felt so crucial for Tehran. What happens after September may not strictly adhere to diplomatic intentions, he cautioned. “We’ve seen what happens when decisions about security go wrong,” he said, pondering the future trajectory of ISIS and its implications for Iran’s regional influence.