The US aid spending watchdog for Afghanistan warned last month that the US military had little or no means of knowing the capability of the Afghan National Defense and Security forces (ANDSF) when required to operate independently of the US forces, despite spending $88.3 bn on security-related reconstruction in Afghanistan up to March 2021.

The Taliban have 80,000 troops in comparison with a nominal 300,699 serving the Afghan government, yet the whole country has been effectively overrun in a matter of weeks as military commanders surrendered without a fight in a matter of hours.

It is a tale of two armies, one poorly equipped but highly motivated ideologically, and the other nominally well-equipped, but dependent on NATO support, poorly led and riddled with corruption, Guardian reported.

It found the US military to be persistently over optimistic about Afghan military capability, even though it had no reliable evidence to make that assessment, and said the departure of thousands of US contractors, agreed by the US with the Taliban in 2020, "could significantly impact the sustainability of the ANDSF, in particular their ability to maintain aircraft and vehicles".

The watchdog had, it said, repeatedly warned about "the corrosive effects of corruption" within the force. With its reliance on advanced equipment, and with widespread illiteracy in its ranks, the force could not reliably maintain its strength and combat readiness.

Of the $88.3 bn spent, the watchdog said: "The question of whether that money was well spent will ultimately be answered by the outcome of the fighting on the ground, perhaps the purest monitoring and evaluation exercise."

The report's clear warnings are likely to be reviewed by US Congress as it seeks to understand why such vast spending on training the Afghan military has led to a collapse to the Taliban in a matter of weeks, leaving western politicians shocked and bemused.

It also raises the question of why the Biden administration ever thought it was safe to leave Afghan forces on their own after a decades of dependence on the US for key skills, including air cover, logistics, maintenance, and training support for ANDSF ground vehicles and aircraft; security; base support; and transportation services. The US president said as recently as 8 July that there was no likelihood of Afghanistan being overrun, Guardian reported.

The additional problem was a central government facing a severe fiscal crisis precipitated by the loss of customs revenues and declining aid flows. Many officials complained that they had not been paid for months.

Fear was a further factor. As momentum swung towards the Taliban, fostered by Taliban social media, the speed of events became fuelled by fear of revenge and personal scores being settled under cover of a takeover, particularly in a large city like Kabul.

The Afghan government provided no counter-narrative.

It started its multi billion-dollar training of Afghan forces in 2002 and three years later took control of training both the police and military, so US military trainers have had nearly two decades to ready the Afghan forces for a Taliban insurgency.