The American military and its allies must stay in Iraq even after defeating the Islamic State to ensure that the group does not reemerge, said Defense Secretary Ash Carter on Saturday.
Speaking at the Reagan National Defense Forum in Simi Valley, Calif., Defense Secretary Carter said that while the militants are expected to face lasting defeat, "there will still be much more to do after that to make sure that, once defeated, ISIL stays defeated."
"We'll need to continue to counter foreign fighters trying to escape and ISIL's attempts to relocate or reinvent itself," he said in his closing remarks at the national policy summit. "To do so, not only the United States but our coalition must endure and remain engaged militarily. In Iraq in particular, it will be necessary for the coalition to provide sustained assistance and carry on our work to train, equip and support local police, border guards and other forces to hold areas cleared from ISIL."
The Islamic State's potential loss in the continued battle over the city of Mosul, the last IS stronghold in Iraq, could be the "greatest blow to their vision of a caliphate that stretches from across North Africa, through the Middle East, to Pakistan," as Scott Peterson reported for The Christian Science Monitor in October.
“We're not just talking a symbolic victory [over IS in Mosul]; this is going to be the death blow for IS the caliphate,” Hayder al-Khoei, a visiting fellow at the European Council on Foreign Relations (ECFR) in London, told the Monitor at the time.
He cautioned, however, that the IS losing Mosul would not mean that the jihadists will disappear.
"They are still going to be a very powerful, a very relevant terrorist organization," Mr. Khoei said. "And if anything, the loss of their state will increase the frequency of their attacks, both in the West and certainly in Iraq and Syria. This is simply for them to say, 'We are still relevant. The loss of our capital in Iraq isn't going to make us go away.'"
Speaking on Saturday, Carter said the Obama administration has directed the Joint Special Operations Command to prioritize destroying the Islamic State's ability to carry out terror attacks in the West.
The Defense Secretary did not specify for how long the continued US military presence may be necessary in Iraq, or how many troops would be needed – decisions likely to be handed over to the Trump administration after President-elect Donald Trump's inauguration in January.
For now, as his time as Defense Secretary comes to an end, Carter said he is focusing on ensuring a smooth transition to his Trump administration successor. President-elect Trump announced earlier this week that he plans to nominate retired Marine Gen. James "Mad Dog" Mattis for the position.
"I've worked with Jim for many years, he's a friend, and I hold him in the highest regard," Carter said.
This report contains material from the Associated Press.