Washington's Special Inspector General for Afghanistan Reconstruction said the U.S. has provided more than $104 billion to rebuild Afghanistan -- more money than the United States has spent on reconstruction for any one country in history.
But John Sopko said despite the massive investment, corruption and the narcotics trade are flourishing, and Afghanistan is unable to pay for and maintain projects the U.S. has started.
"The bottom line," Sopko said Friday in remarks at Georgetown University, "it appears we've created a government that the Afghans simply cannot afford."
The US and international donors fund more than 60 percent of Afghanistan's national budget.
Even as the deadline for withdrawing all international combat troops from the country nears, Congress has appropriated $16 billion in additional reconstruction money.
Sopko said the United States so far has failed to effectively deal with corruption in Afghanistan. He added the gap that is "astonishing" given that Afghanistan is one of the most corrupt countries in the world and the US is spending billions of dollars there.
He was equally critical of Washington's failed $7.- billion effort to fight the opium industry. Without an effective counter-narcotics strategy and Afghan political will, Sopko warned, the country could become a narco-criminal state.
Sopko said it is critical to have strong oversight of US spending in Afghanistan, but noted that with the military drawdown, working toward more accountability in an increasingly dangerous environment would be a real challenge.
Sopko, a former prosecutor, was appointed to the post of Inspector General in 2012, and is renowned in Washington for his tough stance on corruption and government inefficiency.