The U.S. has spent more on Afghan reconstruction in real dollars than it did rebuilding Europe under the Marshall Plan after World War II, Sopko has said -- with much different results. The modest gains in Afghan living standards that have resulted from all that spending could easily plummet amid a deteriorating security situation and endemic corruption, he says.
"We could lose it all and all the investment for the last 15 years if we don't get it right as we go forward," Sopko told NBC News recently.
On the military side, the Taliban controls more of Afghanistan than it has at any time since the start of the war in 2001, American officials acknowledge.
In another recent report, Sopko found that after $3 billion in U.S. spending on Afghan roads, 95 percent of the sections his auditors inspected were damaged or destroyed, and 85 percent were maintained poorly or not at all.
In the Herat schools, Sopko says his auditors found a substantial disconnect between the number of students and teachers paid for on the books, and the number who actually attended. Each student or teacher on the rolls is funded by the Afghan government, which in turn is funded by international donors, the largest of which is the U.S.
While officials reported an average enrollment of 2,639 students at each of the 25 schools in Herat province, an average of 561 students were observed at each school, or 23 percent of the reported numbers.
"Our observations from these site visits indicated that there may be problems with student and teacher absenteeism at many of the schools we visited in Herat that warrant further investigation by the Afghan government," Sopko wrote. "We also observed that several schools we visited in Herat lack ... electricity and clean water, and have structural deficiencies that are affecting the delivery of education."
At another school in Herat City, a school official noted that 1,287 students attended the school on a normal day.