The report was required under the 2013 defense authorization act that called for an independent study on the future of security in Afghanistan. The Pentagon contracted with CNA, a federally funded research center, for the study that was carried out by a panel of experts, including four retired generals and several former defense and national security officials.

The Islamist insurgency has been “considerably weakened” since the 2009 surge of 21,000 additional troops in the country. However, the Taliban “remains a viable threat to the government of Afghanistan.”

“The coalition’s drawdown will result in a considerable reduction in counterinsurgency and counterterrorism operations by Afghan, U.S., and NATO forces,” the report said.

The Taliban are expected to regenerate their capabilities in sanctuaries in Pakistan as military pressure on them declines.