John F. Sopko's assessment has its doubters, but he paints a stark picture of security so shaky and roads so dangerous that inspector general staff take helicopters to the airport rather than drive. Contracting can be so shoddy, buildings crumble months after they're built.
More than 700 schools have been closed because of the ongoing insurgency. Bribery, money laundering and other forms of corruption continue to sap revenues. And despite at least $7 billion in counternarcotics spending, opium production hit 3,300 tons in 2015 -- exactly the same level it was in 2000, according to Sopko.
"Fifteen years into an unfinished work of funding and fighting, we must indeed ask, 'What went wrong?'" Sopko said in remarks prepared for delivery at Harvard University Thursday. "The reconstruction effort in Afghanistan is in a perilous state."
Sopko, who has a background in international law and as a congressional investigator before being appointed by Obama in 2012, said the U.S. military drawdown has created blind spots for the Pentagon, which isn't as able to collect reliable information on Afghan security capability and effectiveness.
Conditions there, he said, "illustrate a grim strategic threat."
Sopko pointed out that Afghanistan has made some progress, however, and that U.S. agencies have scored successes.
"Despite ongoing violence, the Afghan people are healthier, better schooled and less impoverished than they were 15 years ago," he said, but added, "The record is decidedly mixed."
The State Department did not respond to a request for comment on Sopko's findings.
Some analysts, however, say Sopko overemphasizes the connection between waste and corruption and the difficulties Kabul faces.
"The current challenges in Afghanistan are not correlated with wasteful projects," said Seth Jones, director of the International Security and Defense Policy Center at RAND and a former advisor to the commanding general of the U.S. Special Operations Forces in Afghanistan.
Jones assessed that those challenges have more to do with the ability of Taliban insurgents to find and secure a sanctuary in neighboring Pakistan, an ineffective government in Kabul and lackluster Afghan security forces plagued by poor leadership and low morale.
"The reality is that outside powers -- including the United States -- have a limited ability to improve the quality of governments," Jones said. "Reform needs to come from within."
President Barack Obama flagged Afghanistan's problems in October, when he announced he would significantly slow the withdrawal of U.S. troops
, leaving 9,800 soldiers in the country through 2016 to train Afghan forces and go after al Qaeda.
"After so many years of war, Afghanistan will not be a perfect place," he said. "There will continue to be contested areas" and Afghan forces still aren't as strong as they need to be as they face an intensifying Taliban insurgency.
Afghanistan is a key part of a counterterrorism network the U.S. uses to deal with threats and prevent attacks
on the homeland, Obama said. And maintaining troop levels to better train Afghan soldiers is crucial "because if they were to fail, it would endanger the security of us all," he said.
Sopko describes Taliban-related security concerns as "death of a thousand cuts."
They repeatedly carry out hit-and-run assaults on Afghan army and police checkpoints and small outposts, capturing weapons, inflicting casualties and eroding the credibility of the government in Kabul, he said.
A March report by the U.N.
said that "for 2016, survival will be an achievement" for the Afghan government, which faces a contracting economy, ongoing Taliban attacks, a stalled peace process, a divided political setting and an ongoing need for international support.
Since 2002, Congress has appropriated more than $113 billion to reconstruct Afghanistan, an amount that, when adjusted for inflation, exceeds total spending on the Marshall Plan that helped rebuild Western Europe after World War II.
Despite all that money -- and sometimes because of it -- the problems have mounted.
Contracts have been plagued by bribery and price-rigging and "holding high-ranking or politically connected individuals accountable continues to be a major challenge," Sopko said.
Security, which accounts for about $68 billion of U.S. spending since 2002, has also been undermined the purchase of planes that weren't suited to their task and shoddy or incomplete work.
Sopko detailed the case of the "melting building" in one province to bring that point home.
The Pentagon contracted an Afghan firm to build a dry-fire range, which is used to train people on stance, aiming and weapons familiarization. Four months after the contractor finished the building and was paid in full, the buildings began to "melt" and crumble in the rain because the firm had used substandard materials.
The building was demolished at additional cost to the American taxpayer, Sopko said, but Pentagon officials failed to hold the contractor accountable.
In another case, the Afghan contractor of a newly built hospital didn't fix failures pointed out by U.S. officials, which meant newborn babies were being washed with untreated water from a nearby river.
Older children are suffering as well, Sopko said, describing a March announcement by the Afghan Ministry of Education that more than 2.5 million children weren't able to attend school because of the war.
This, he said, was one of many consequences of insecurity that "are less headline-grabbing, but are still evil omens for the future of a desperately poor and largely illiterate country."