I am more interested in the big picture of counterinsurgency, rather than the specifics of tactics and the internal squabbles of militarists surrounding it. For examples from a more military planning perspective see here, here, and here.
The first point to make is that “counterinsurgency” shouldn’t be seen just as a military doctrine, but as a product of historical circumstance as well. It is a predictable reaction to a colonial situation. The American love affair with counterinsurgency began, after all, when it appeared that Donald Rumsfeld’s ideas about military strategy were less than brilliant and thus some generals in the field -- tasked with managing an ill-conceived adventure in Iraq and a neglected one in Afghanistan -- had to figure out how to achieve some semblance of stability. It was elevated to an all-encompassing “doctrine” by a crowd of enterprising soldier-academics and craven politicos trying to sound smart.
The main problem with the theory of counterinsurgency is that it rests on two faulty assumptions. The first is that foreign powers can with relative ease create states in occupied territories. State-building from afar is, of course, not impossible: most postcolonial societies inherited their states from the colonial period. But these proto-states took decades to build and even then were pretty shitty. Africa's many weak states attest to this postcolonial legacy.
Northern Ireland is often cited by many as a “successful” counterinsurgency, but its state-building process was an incredibly difficult and slow affair. Despite hundreds of years of colonizing the island, the British government was largely unable to build a functioning state after 1973, when the Stormont parliament was abolished (though it had effectively ceased to function in 1969). Indeed, some argue that it wasn’t until the 2010 Hillsborough Castle Agreement that an actual government was finally established in the region.
Iraq -- the new model for successful counterinsurgency -- further illustrates the state-building problem. The government in Baghdad wasn’t so much built from scratch as reformed from the pre-invasion state, minus the army.
Afghanistan is no Iraq. Not only has the country never had a viable state historically, but the rumors of the Afghan state's current existence have been grossly exaggerated. Dues to the weakness and corruption of Afghan security forces in particular, providing citizens a credible and secure alternative to insurgent rule is incredibly difficult. The Obama Administration is finally coming around to this reality, which they so charmingly refer to as “Afghan good enough.”
The second problem is that proponents of counterinsurgency assume that states have the unlimited resources required to implement it and that publics have the unlimited patience to see the plan out. This is generally an untenable assumption, especially for foreign occupiers. Much of counterinsurgency theory were formulated by colonial and neocolonial militaries: i.e. the British, the French, and the United States (first in the Philippines, later in Vietnam). And this is why counterinsurgencies tend to have historically been unsuccessful: the colonial states were unable, and their populations unwilling, to commit precious resources that counterinsurgents demanded and accept their indefinite time-frame for success.
Consider the situation in Afghanistan. The Obama Administration’s rethink of the whole adventure probably began when it became apparent that the current counterinsurgency strategy would take at least ten years and cost a trillion dollars to implement. Given the plummeting popularity of the war, such a commitment is thoroughly impossible.
The counterinsurgency crowd doesn’t seem to understand these basic realities: states are hard to make and the public isn’t willing to spend the time or money they demand to see their plans through. With Gen. Allen continuing to insist that he can build a viable Afghan state out of nothing more than abstract doctrine, it’s no wonder that he’s being consulted less on ending the war. But, like a good soldier, he’s apparently implementing the post-counterinsurgency plan on his way out
But, for all its problems, counterinsurgency puts a kind face on militarism, what with all its road-building and well-digging.