From the very beginning of its intervention in Afghanistan, the US sabotaged its own efforts by feeding corruption in the country’s government and the security forces meant to fight the Taliban, according to a new report by a US Congress watchdog.

“Corruption undermined the US mission in Afghanistan by fueling grievances against the Afghan government and channeling material support to the insurgency,” says the Special Inspector General for Afghanistan Reconstruction (Sigar) in the report released on Wednesday.

More than $100bn in aid after 2001 helped enrich patronage networks and powerbrokers, discrediting international donors in the eyes of the Afghan population. And whenever the US did attempt to improve accountability, the Afghan government resisted, the report says.

As a result, corruption – which had permeated Afghan public life for centuries – swelled to unprecedented levels.



“The ultimate point of failure for our efforts … wasn’t an insurgency. It was the weight of endemic corruption,” former US ambassador Ryan Crocker told the authors of the report.

These assertions are not new. But coming from an agency established by the US government, they are potent.



Two main causes of Afghanistan’s staggering levels of corruption are the sheer volume of aid and a lack of oversight. At times, US reconstruction assistance – separate from military spending – exceeded Afghanistan’s GDP, far beyond the 15% to 45% of GDP developing states can normally absorb, the report says.



Another source of corruption is the illegal drugs trade, which grew seven-fold from 2002 to 2014.



Sigar partly blames the Afghan government, though it has lived up to some commitments to donors, such as forming an independent anti-corruption committee. The committee, however, receives “uneven political support”, Sigar says, and has no legal authority.



In one damning episode in 2010, Hamid Karzai, the president at the time, ordered the release of an aide who had been caught on wiretap demanding a bribe to thwart an investigation into a money transfer firm accused of stealing $2.78bn. Meanwhile, the same aide was also receiving payments from the CIA, even as he was targeted by US law enforcement agencies.

The report – which is the first of several upcoming summaries of “lessons learned” – comes at a time of intense fighting across Afghanistan. In recent weeks, the Taliban have come close to capturing several provincial capitals. Lashkar Gah, in Helmand, is virtually surrounded. In Uruzgan, where Australians led international efforts for four years, government forces only barely staved off an attack last week.



Sigar’s conclusions cohere with the view of analysts in Kabul. There is a direct link between US funds feeding corruption and the erosion of security, said Toofan Waziri, a security analyst.



He said many police officials vie for top jobs in volatile provinces, not to battle insurgents but to get a foot into various smuggling businesses. That is the case in opium-rich Helmand as well as the northern mining province of Badakhshan.



Cash-strapped soldiers, whose salaries are paid late if at all, are also selling fuel and ammunition to the Taliban, Waziri said.



That trend was confirmed to the Guardian by a western security source who said both the US military and the Afghan government have launched investigations into the sales of ammunition to insurgents.



The lack of results in eradicating corruption has disappointed supporters of President Ashraf Ghani, a former World Bank technocrat who campaigned on pledges to do just that. Since he took power in September 2014, Ghani has failed to recover almost $1bn stolen in a giant fraud at Kabul Bank.



Anti-corruption efforts have also been hampered by Ghani’s perpetual tussles with his government partner Abdullah Abdullah.