The recent New Year's Day attack in New Orleans, where a man allegedly drove a truck bearing an ISIS flag into a crowd on Bourbon Street, killing 15 and injuring dozens, has brought the persistent threat of the Islamic State back into focus. While the FBI hasn't officially linked the suspect, Shamsud-Din Jabbar, directly to ISIS, reports suggest he expressed support for the group online.

Law enforcement at the scene of the New Orleans attack. (Michael DeMocker/Getty Images)

Security expert Bill Roggio, of the Foundation for Defense of Democracies, cautions against premature declarations of ISIS's defeat. "These groups are resilient," he explains. "They may face setbacks, but they persist. ISIS still presents a danger from Afghanistan, maintains a substantial network in Africa, and remains active in Iraq and Syria."

While this incident doesn't necessarily signal an ISIS resurgence, Roggio notes that the group is encountering less resistance in some regions. The 2021 Afghanistan withdrawal and the recent fall of the Assad regime in Syria to Hay’at Tahrir al-Sham have created power vacuums, potentially allowing ISIS and similar groups to exploit these instabilities.

Celebrations in Damascus following the fall of the Assad regime. (Ali Haj Suleiman/Getty Images)

Although ISIS-K, the group's regional affiliate, hasn't significantly expanded in Afghanistan since the Taliban takeover, it also faces less opposition. "The Taliban and ISIS are adversaries," Roggio states. "The Taliban targets ISIS, even without U.S. presence. This gives ISIS more room to maneuver."

An ISIS fighter. (Reuters Photo)

Roggio emphasizes that in Afghanistan, the Taliban and al Qaeda pose a greater threat to the West than ISIS, but ISIS has "more space to operate" with the Assad regime's collapse. He adds, "The Assad regime, despite its horrific nature, did combat ISIS. Its absence leaves another terrorist group in nominal control of significant Syrian territory."

The planned U.S. military withdrawal from Iraq by 2026 raises further concerns. Experts worry about ISIS's continued threat and the potential endangerment of American troops in Syria. Renegotiations of the withdrawal plan, considering the Syrian situation, haven't been announced. It's also uncertain how the incoming Trump administration will address the ISIS threat and U.S. troop deployments in the region, given Trump's previous focus on withdrawing forces from Afghanistan.

U.S. service members in Baghdad. (U.S. Army)

Roggio stresses the importance of a sustained U.S. presence to counter ISIS and other threats. "Without the U.S., groups like ISIS will flourish in the prevailing lawlessness," he warns. "As we saw in Afghanistan, relying on terrorists to fight other terrorists is a flawed strategy."