The authors of the report by the Massachusetts-based National Bureau of Economic Research say they analysed 15 months of data on military clashes and incidents totalling more than 4,000 civilian deaths in a number of Afghan regions in the period ending on 1 April.
They say that in areas where two civilians were killed or injured by Nato's International Security Assistance Force (Isaf), there were on average an extra six violent incidents between insurgents and US-led troops in the following six weeks.
The report concludes that civilian deaths frequently motivate villagers to join the ranks of insurgents.
"In Afghanistan, when Isaf units kill civilians, this increases the number of willing combatants, leading to an increase in insurgent attacks."
"Local exposure to violence from Isaf appears to be the primary driver of this effect."
This is not an anti-occupation study. Rather, it supports McChrystal's counterinsurgency (COIN) policy of restraining military actions in order not to provoke resistance. (For background on this, see here.) This policy is intended to secure loyalty among the natives and enable the occupiers to build a client state structure, but its logic is to prepare the way for a plausible exit, one in which the US doesn't look like it just had its ass handed to it. The prevailing opinion in the military establishment seems to be that COIN didn't work. The strategy of outright high-octane aggression didn't pacify the insurgency either, however, and it's been guzzling revenue for few discernible rewards at a time when the Pentagon is under increasing pressure to reduce its expenditure - the empire is in no danger of going broke immediately, but its resources are seriously stretched. So Obama is sticking with COIN for the time being, while explicitly endorsing negotiations with segments of the Taliban. This is hitched to an ostensible initial withdrawal date of July 2011. There can, of course, be policy reversals. But the American economy is in a bad way, and the empire's global power is deteriorating. The more strategically-minded elements in the ruling class may consider it advisable to adapt to this situation rather than continue with the adventurist policies of Obama's predecessors.