Daniel Wiser of the Washington Free Beacon reports on a discouraging new assessment of President Obama’s approach to terrorist threats in the Middle East.

Al Qaeda or the Islamic State could launch a mass-casualty attack on U.S. soil if the Obama administration does not alter its current strategy to defeat the terrorist groups, according to a new report that lays out recommendations for a revised U.S. counterterrorism policy.

The report from the American Enterprise Institute estimated that, under President Obama’s current strategy and military and diplomatic efforts, the terrorist groups could control “at least twice as much territory and population—in Iraq, Yemen, North Africa (especially Libya), the Sinai, and Syria—and with an army of regular and irregular fighters at least twice as large within two years.” Those safe havens would allow al Qaeda and the Islamic State (also known as ISIS or ISIL) to plot more attacks against the United States and the West.

“As these conditions worsen, al Qaeda, ISIS, or both will carry out a mass-casualty attack against the US: it is a question not of if, but rather of when,” the report said. “Even more worrisome is our assessment that, if we fail to stop the extremists from taking territory and undermining states like Pakistan, al Qaeda or ISIS will obtain weapons of mass destruction, and then it will be too late to act.” …

… The authors of the AEI report, including two counterterrorism experts, Frederick Kagan and Katherine Zimmerman, said that a retooled strategy to defeat terrorist groups would not require large deployments of hundreds of thousands of U.S. ground troops. In fact, such a strategy would be “unnecessary and inadvisable,” they said, and should focus instead on training local partner forces to conduct counterinsurgency campaigns and work with civilian populations. U.S. forces employed a similar counterinsurgency strategy and achieved some success when they had a larger presence in Iraq and Afghanistan.

Still, the U.S. military will likely need thousands more boots on the ground—trainers, advisers, and, when necessary, combat troops—than Obama is currently advocating, they said.

“Insurgencies have a tendency to flare up repeatedly, even after being suppressed with all the skill at the command of the counterinsurgents, while civil wars are inherently generational conflicts,” the report said. “This fact might mean that the U.S. and its partners will have to leave sizable numbers of troops on the ground throughout the world, perhaps for decades, as we had to do following World War II and the Korean War.”