President Obama yesterday announced his decision to send 17,000 extra troops (two brigades and support troops) to Afghanistan in the coming months, bringing the total American troop presence there to over 50,000. This has been in the works for some time. It comes as the administration conducts several reviews on Afghan policy.

You might say we are putting the cart before the horse, sending troops at a problem just as we reconsider our strategy for confronting it. On the other hand, our existing strategy, which is to prop up the Afghan state with US firepower, seems unlikely to change under Obama. Despite recent sensible comments about the limits of what we can accomplish in Afghanistan, Obama’s team likely remains committed to state-building there. Given that goal, it is hard to see why we should stop at two brigades. We could send five and still have a low force-to-population ratio, judging by historical ratios for counter-insurgency campaigns.

A stable Afghanistan is neither necessary to US security nor obviously possible at reasonable cost, as I have periodically written. It is not evident that Al Qaeda types would again find haven in Afghanistan should we go. But assuming that they would, there remains an alternative to trying to overcome Afghanistan’s anarchic history. We could attack only the remaining jihadists, their allies, and insurgents who will not settle for local power. That would require only a small U.S. ground presence, airstrikes and local allies.

Pundits tend to assume that counterinsurgency and state-building are identical — foreigners enforce the state’s claim to a monopoly on violence to gain it support and crowd out alternative authority structures. But there is another counterinsurgency strategy out there, which is to allow the insurgency local power, to appease it as part of a bargain. The key tactic that brought lowered violence in the Sunni part of Iraq – bribing insurgent militia leaders to cooperate with us — undermines the Iraqi state, sacrificing our stated goal for a simpler one.

While we’re on the subject, I see Matt Yglesias supports the troop increase because it will lessen the need for airstrikes, which too often kill civilians. That seems backwards. Even with 12,000 new combat troops, our forces will remain a relatively small force in a large mountainous region. That means operating in dispersed contingents with limited firepower and therefore depending on air support in firefights. The new troops will likely provoke more combat and more supporting airstrikes, at least in the short term.