The United States made a decision to withdraw from Afghanistan several years ago. That decision carried with it an inevitable logic. Once the United States resolved itself to leave at any cost, its failures up to that point were laid bare, as were the vulnerabilities of the government it had spent more than a decade building. The door was opened for the enemies of the regime of President Hamid Karzai -- the man who has been synonymous with the post-Taliban government. All that was left to do was wait for the American pullback.
U.S. Failures
Elements within the U.S. government have not been shy in their criticisms of the Afghan government and the Afghan military as being corrupt and incompetent. Some units have been effective, but it is well known that the Taliban created a program designed to penetrate post-Taliban institutions shortly after those institutions were created. At the most senior level, the Taliban paid, through family members, substantial sums to buy the loyalties of individuals. These bribes worked partly because there was a lot of money involved and partly because people realized that once the United States left, government loyalists would be on their own. This is not a phenomenon unique to Afghanistan -- people would prefer to live, and those in question were hedging their bets.
Separately, there was a significant enlistment of Taliban sympathizers into the incipient Afghan military. This trend was less formal but even more effective. Soon there were Taliban supporters at several levels of the military, something we saw during the wave of unexpected assassinations of NATO personnel by people believed to be loyal to the regime. These are what came to be called green-on-blue attacks.
Therefore, Afghan forces are fundamentally unreliable. Not everyone has to be in contact with the Taliban to render the force unusable; a single person prepared and able to signal planned operations renders any operation either useless or disastrous.
When it created the Afghan force, the United States was extraordinarily lax in monitoring recruitment. Of course, the defense is that most of the trainers had no way to distinguish the loyal from the subversive. This was widely experienced in Vietnam. There was a bartender at a favorite American hangout in Saigon who turned out to have been a colonel in the North Vietnamese Army for years.
But this brings us to one of the most serious U.S. failures in Afghanistan: a cultural contempt for the Taliban. As it did in Vietnam, Washington failed to understand that the absence of U.S.-style bureaucracy and technology didn't mean that the enemy could not identify opportunities or that it lacked the will to take advantage of them.
The Taliban have suffered heavy losses, but in the end what matters on the battlefield is not the absolute size of the force but the correlation of forces. The problem with the Afghan force is that while there are some reliable units, it is impossible to identify them. Moreover, Karzai's ability to cleanse the force of Taliban sympathizers was thwarted by the fact that his own bureaucracy was seen as unreliable. As the United States learned from the South Vietnamese army and the Vietnamization program, the penetration of your force makes your operations ineffective. It gives the enemy insight into your tactical organization and strategic thinking and, most important, it sows uncertainty and distrust.
In a civil war, the viability of the government is not a function of ideas such as legitimacy or international recognition. It is a function of your ability to reliably assert your presence in regions. There are tribes and other groups in Afghanistan that have a high degree of coherence. It is these entities -- not the Afghan government -- that can and will challenge the Taliban. There are a few possible outcomes, including total fragmentation, but the creation of a sustainable national government by the Karzai regime isn't one of them. More important, the United States doesn't believe it is a possibility either.