In the wake of Vietnam, U.S. military planners spent decades figuring out how to avoid such military morasses in the future. The result was the so-called “Powell Doctrine”: the idea that U.S. military power should be applied only in the presence of a clear exit strategy, only with overwhelming force, and only with encompassing diplomatic support from allies. Following the Powell Doctrine, the thinking went, America’s wars would be swift and decisive, and the US could be sure to never again get bogged down fighting natively-supported insurgencies while propping up dubious ‘friendly governments’.
Until, of course, Afghanistan and Iraq once again saw America getting bogged down fighting natively-supported insurgencies while propping up dubious ‘friendly governments’. Many have blamed the US’s troubles in these wars on its failure to abide by the Powell Doctrine. After all, in neither Iraq nor Afghanistan did the US have an exit strategy, apply overwhelming force (in the occupation, that is) or enjoy overwhelming diplomatic support. Indeed, post-Iraq this conclusion has engendered the same sort of mentality that characterized US military thinking post-Vietnam: a desire to avoid at all cost getting embroiled in foreign wars, let alone with boots on the ground.
My point here is that this sort of thinking, including the Powell Doctrine itself, is wrong-headed. It is wrong-headed because it plans for the sort of wars the U.S. wants to fight, rather than the sorts of wars it most likely will fight.
Historically the Powell Doctrine had two consequences. On the one hand, it lead to a cleanly-executed campaign in the first Gulf War. But on the other hand, the Powell Doctrine was also among the chief factors that lead America to be woefully unprepared for the sort of tasks it faced in Iraq and Afghanistan. It took the US military several years of dreadful experience in Iraq to develop a proper counterinsurgency strategy precisely because for decades it had been told it would not be doing any counterinsurgency.
The bottom line here is that it is to easy to say that in Afghanistan and Iraq America did not sufficiently carefully heed the Powell Doctrine. Of course it is of vital importance prior to any military engagement to consider the possible conditions of departure, or the opinions of important allies. But this should not overshadow the insight that America is a powerful country with powerful interests and commitments, which will for the foreseeable future be called upon to involve itself in foreign conflicts, including militarily. America’s interests, both its material interests and the interests pertaining to its geopolitical standing in the world, will often call precisely for the complicated, limited military engagements that the Powell Doctrine forbids. The current situation in Syria is just one example of this general phenomenon.
As such, it is simply facile and unrealistic for strategic thinkers to counsel the US against limited, counterinsurgency warfare. The US will, at some points, be called upon to get involved in such conflicts, and it will, at some points, require boots on the ground. The trick will be to conduct such campaigns, where goals and exit-plans are often murky and susceptible to change, as well as possible. This is what the US military should be planning for.