The lack of Afghan government legitimacy and good governance, along with the inability to disrupt Taliban support and supply systems, are the leading indicators of defeat, the study said. All successful counterinsurgencies worldwide between 1978 and 2010 achieved such enemy disruption, “while none of the losers were able to.”

Compared to counterinsurgencies worldwide between 1978 and 2010, all of the winners achieved the latter, “while none of the losers were able to.”

The study was released by Rand’s National Defense Research Institute, funded by the Pentagon and the U.S. military. It follows an earlier report assessing 30 earlier counterinsurgency campaigns worldwide — only eight of which were deemed successful.

The assessments were based on what Rand called the “Delphic” method, in which 15 factors were judged “good” for counterinsurgency, while 12 were judged “bad.” When experts judged each of the 30 past campaigns — including the Soviet Union in Afghanistan, the contras in Nicaragua, and government counterinsurgencies in Turkey and Algeria, the method picked the actual winner every time.

The current counterinsurgency in Afghanistan was scored by 11 experts, including Rand staff with expertise or deployment to Afghanistan, “serving field-grade U.S. military officers with multiple [and recent] deployments to Afghanistan, military veterans who were current on [counterinsurgency] research, university faculty members, journalists, and experts from other prominent think tanks.”

The campaign scored less than the worst of the successful counterinsurgencies, and more than the best of the failures.

Among the “good” factors, Afghanistan’s government was judged “a partial or transitional democracy,” albeit one that was dysfunctional. The panel gave the U.S.-led coalition points for gathering intelligence leading to the killing or capturing of Taliban leaders, for disrupting their offensive operations and for dominating air operations.

On the negative side, the experts judged the counterinsurgency force was perceived to be an “external occupier,” whose actions contributed to “substantial new grievances” claimed by the insurgents.

Not surprisingly, Rand recommended “seeking further improvements to increase good factors and decrease bad factors in order to increase confidence and the likelihood of victory in Afghanistan.”