Spencer Ackerman says:
I’m not saying I know this would happen. I don’t know that it would. Much depends on the circumstances under which the Taliban returns to power. (A power-sharing deal; an element of reconciliation; outright victory; etc.) These are questions that need to be studied, not off-the-shelf answers just out of reach of the debate. There are good questions being asked of what “safe haven” really entails, and to the pot let’s add the concept of strategic depth.
One might add that the phrase “Taliban returns to power” is not entirely clear on its own terms. In what sense was the Taliban “in power” in the past? Did they have secure, stable control over the entirety of Afghan territory? Well, no, they didn’t. Just like Hamid Karzai’s government today they exercised effective control over a bunch of Afghanistan, plus armed groups trying to overthrow them controlled a bunch of territory, plus there was some anarchy and battlegrounds and such. The Taliban being “in power” meant they controlled the bulk of Afghanistan and they controlled Taliban.
But bracketing for a moment the issue of how much the existence of a “safe haven” mattered to 9/11, it’s not clear that the “safe haven” issue had all that much to do with the “in power” issue. You don’t need Kabul to be able to provide a safe haven. Nor do you need the majority of Afghanistan. Afghanistan’s almost as big as Texas; you could presumably fit a safe haven into a rather small fraction of the country.
Given that Afghanistan is big, Afghanistan is ethnically diverse, Afghanistan lacks a proper road network, Afghanistan contains multiple armed groups capable of acting independently, Afghanistan lacks a tradition of effective central government, and Afghanistan has been in various configurations of civil war for almost thirty years, I think it’s crucial to always remember that there are a wide range of possible scenarios between “Karzai has effective control over all of Afghanistan” and “the Taliban has effective control over all of Afghanistan.”