Pakistan is the key nation where US interests are most challenged.  While true that the former Taliban government in Afghanistan gave succor to Osama bin Laden and al-Qaeda, the Taliban itself largely originated from Pakistan as part of complex local and geopolitical issues including its conflict with India.  

Fundamentally, America's interest in Afghanistan, while significant, must be looked at within a global framework.  Simply put, US resources must be built back up so that it can take on these kinds of projects.  In the interim, they must be judiciously deployed while retaining the ability to confront other simultaneous challenges.  Though a reconstituted al-Qaeda within Afghanistan must be dealt with immediately, this does not necessarily require Afghanistan to become a democracy in the traditional, western sense.  

Both President Bush and President Obama seem allured by the notion that the only way to keep al-Qaeda off balance is to force Afghanistan to become something it has never been in its history- a unified state with a reasonably strong central government. However, even a federated government may not do justice to the various tribal loyalties in the nation.  This raises serious questions about any long-term success for creating a stable state, even if Gen. McChrystal's counterinsurgency strategy works as intended.   

With all choices in the region deeply problematic, it seems the least bad one is to focus on preventing Afghanistan from being an easy base of operations for terrorists while shifting to regional diplomacy to dry up the wellspring from which al-Qaeda grows. This could be done by taking several steps:  

1. slowly disengage most current ground forces in Afghanistan without telegraphing specific time lines;
2. retain an intelligence presence complete with financial incentives to maintain relations with various tribes;
3. retain a rapid strike capability with naval and air assets that can act upon any intelligence;
4. work to develop public/private partnerships with NGOs to continue an influx of capital into Afghanistan to construct schools and basic infrastructure
   

Though a far cry from "doubling down" in Afghanistan, this would also not be a  repeat of the mistake made after the US left Afghanistan to its inner turmoil in the early 90s.  

Meanwhile, the US must continue to push Pakistan to keep neo-Taliban elements contained within the Federally Administered Tribal Areas and away from the most significant population centers. This must be done with or without the current rather weak civilian government.  

The US also needs to reengage India more than it has since Obama took office. As India is a rising power in the region, it must be considered the key ingredient in keeping the pot from boiling over.  It would clearly not be in India's best interest if Afghanistan devolves back into a jihadist playground.  Given this, it may even be possible to entice India to play a limited role on the ground in Afghanistan as the US reduces its own footprint. 

Obviously, there would need to be guarantees to Pakistan that this is not part of a conspiracy to surround it.  However, this may add another incentive for Pakistan to fight more aggressively against those destabilizing Afghanistan to avoid a major expansion of Indian influence.  

The US can not abandon Afghanistan to the vicissitudes of fortune.  Al-Qaeda cannot be allowed to again find sanctuary there.  Yet, with other problems looming, including the possibility of a military altercation with Iran or the need to recalibrate forces in Central/Eastern Europe due to revanchism in Russia, the US cannot allow its flexibility to be permanently constrained while fighting to establish something unlikely to be successful in the long-term.  US interests are  too broad for it to become strategically myopic."