Andrew Exum calls the increased attacks on US and allied forces by their Afghan counterparts "the most serious tactical challenge to the NATO coalition since the war in Afghanistan began almost 11 years ago":
Thus far, the peoples of the Western alliance have been patient when troops have fallen in combat with the Taliban. They have understandably been far less patient, however, when the very Afghans they were sent to help have opened fire. The recent French decision to withdraw from Afghanistan out of step with its allies, for example, was in part motivated by green-on-blue killings ["blue" is friendly, "red" is enemy, and "green" is the host nation] that outraged the French people and political class. Operationally and tactically, these attacks affect the way in which Western troops do their business in Afghanistan. They cannot help but be more suspicious of their Afghan counterparts — and are indeed now ordered to always be on the lookout for attacks by their putative allies.
Exum follows up:
These attacks are similar to the epidemic of military suicides in that we can discern an obvious pattern, but it remains difficult to determine what, precisely, is causing the problem. Once you dig deeply into each incident, they begin to seem sui generis — each prompted by a unique set of circumstances. That makes them arguably more difficult to address than Taliban infiltration, which is a counter-intelligence problem for which we have some precedent. If these attacks instead represent a structural erosion in the relationship between coalition and Afghan forces, that's a lot tougher to fix.
The Dish 