Circular Reasoning in Afghanistan

Yesterday’s New York Times glossed one reason why some U.S. officials think we need to stay in Afghanistan in force:
But for years, throughout the Bush administration and into the Obama administration, American officials have been making trips to Pakistan to reassure its government that the United States has no intention of pulling out of Afghanistan as it did 20 years ago, after the Soviets retreated from the country. Inside the Pakistani Army and the intelligence service, which is known as the ISI, it is an article of faith among some officers that the United States is deceiving them, and that it will replay 1989.
If that happens, some Pakistanis argue, India will fill the void in southern Afghanistan, leaving Pakistan surrounded by its longtime enemy. So any talk of exit strategies is bound to reaffirm the belief of some Pakistani officials that they have to maintain their contacts with the Taliban — their hedge against Indian encroachment.
This was definitely a popular line of thought inside the Bush administration and seems to have some continuing sway in the Obama administration (especially because a lot of the personnel—Gates, Luti, Petraeus—is the same) but it seems in tension with the other popular theory that we need to stay in Afghanistan because a Taliban takeover would destabilize Pakistan. Or perhaps it’s better to say that the reasoning is circular. To win in Afghanistan we need to convince the Pakistanis that we’re staying forever, since otherwise they’ll back the Taliban and we won’t be able to beat the Taliban which we need to do as a favor to the Pakistanis. See!
I sometimes think it’s hard for America’s professional soldiers to avoid seeing their presence somewhere as the solution to all problems.