It would be “a complete catastrophe” to pull the entire U.S. force from Afghanistan next year, said Andrew Wilder, who directs Afghanistan and Pakistan programs at the U.S. Institute of Peace and spent years working in the region.

A deterioration in security conditions would hamper oversight of aid projects, possibly making a deeply skeptical Congress even more reluctant to fund Afghan aid.

A smaller staff at the U.S. embassy in Kabul would also make it more difficult to sustain many U.S. aid programs.

“My judgment is no troops, no aid, or almost no aid,” James Dobbins, the U.S. envoy for Afghanistan and Pakistan, told Congress this month. “The political support for the aid comes from the military presence.”