Al Qaeda may have been seriously degraded in recent years, but the Islamic State, formerly known as ISIS, is rising to take its place as the top terror organization in the Middle East.

The group is sweeping through Iraq in a terrorizing campaign to reestablish the Muslim caliphate. Its rapid defeat of Iraqi military troops in the seizure of Mosul last month destabilized the already fragile country, causing what panelists at a Heritage Foundation event titled “The Iraqi Meltdown: What Next?” described Wednesday as a “disastrous setback” for U.S. counterterrorism.

“[The Islamic State] is metastasizing rapidly by feasting on the corpses of the failed states in Iraq and Syria,” said James Phillips, senior research fellow for Middle Eastern affairs at Heritage, who was joined on the panel by Rep. Jim Bridenstine, R-Okla., Jessica Lewis of the Institute for the Study of War, and Steve Bucci, director of Heritage’s Douglas and Sarah Allison Center for Foreign and National Security Policy.

Phillips described the group as a more “malignant, cancerous outgrowth” of al Qaeda that goes beyond terrorism to see itself as a “vanguard of global insurgency.” Although the group’s current focus is regional, Phillips warned it could become a global threat even greater than al Qaeda.

Bridenstine said President Obama’s “politically motivated” decision to withdraw all troops from Iraq was a key factor in the country’s recent deterioration. He said the “disengagement … created a situation for ISIS to destabilize Iraq and establish the caliphate.”

Phillips said the U.S. had “severely degraded” al Qaeda before it withdrew, but the group has proven “extremely resilient” and was able to rebound by “exploiting the mistakes of the Iraqi government and by taking advantage of the negligence of the U.S. government.

“Heritage warned about the dangers of not leaving behind a residual U.S. presence to help the Iraqis train and to give them greater intelligence and greater counterterrorism capabilities against al Qaeda in Iraq,” Phillips said. The comeback was “predictable.”

Bridenstine said Obama made a big mistake when he upset the “historical precedent” of negotiating status of forces agreements through an exchange of diplomatic letters and rather asked the Iraqi Parliament to establish the agreement.

“The Iraqi Parliament cannot agree on what day of the week it is, let alone try to come up with a status of forces agreement for the United States in Iraq,” Bridenstine said. “[Obama did this] not because it was in the best interest of the United States of America, but because it was in the best interest of his political prospects because he wanted the troops out.”

The U.S. now has a status of forces agreement in Iraq, but the troops are gone and the Islamic State has assumed control of much of the country.

“The president backtracked because it is now in his political interest to have a stable Iraq as people see how ISIS is destabilizing the region and destroying democratic institution,” Bridenstine said.

In addition to this agreement, Phillips said the U.S. must work with a coalition beyond the Iraqi government to defeat the Islamic State. He said this coalition should include the Kurds, Turkey and Jordan along with Sunni Muslims who soon will be “fed up” with living under the Islamic State’s harsh rule.

“This is a regional problem that needs a regional solution before it evolves into a global threat,” he said.

Bucci said the Iraqi government must lead with political and religious aspects in its efforts to defeat the Islamic State, but he says leaving out the military is a “fools errand.

“The military is not the solution for everything, but when you’re fighting hardcore Islamists like the Islamic State is made up of, you’re just as wrong if you leave the military component out,” Bucci said. “Some of those people don’t want to talk to anybody, they don’t want to have negotiations. That’s not their thing. Some of those people you just have to fight.”