When Should We Start Leaving Afghanistan?

Bing West writes in the Wall Street Journal today that it's time to get the hell out of Dodge:

The Taliban are Afghans, to be dealt with by Afghans....On patrols, Afghan soldiers spot the enemy 10 times more frequently than do coalition solders. Afghan soldiers are brave, hardy, ill-disciplined, individualistic, temperamental and trustworthy.

A year from now, coalition forces should be able to gradually withdraw, replaced by robust support and adviser units embedded in Afghan security forces. We shouldn’t make this a NATO war, allowing the Afghans to stand back. We’re outsiders, no matter how many schools we build or cups of tea we drink.

Nothing West says here is especially controversial, really, except for that "a year from now" part.  But why shouldn't we begin withdrawing in 2010?  Al-Qaeda is essentially destroyed, seven years of occupation doesn't seem to have improved our ability to fight the Taliban, and bringing in the DEA isn't likely to help things.  Besides, it's not as if Bing is suggesting that we repeat the mistakes of the past and simply hightail it for the exits:

For things to turn out right for us [...] we have to gradually let the Afghans do their own fighting, while supporting them generously. Afghan forces will need $4 billion a year for another decade, with a like sum for development. The crunch in terms of American support for the war will come a year from now. The danger is that Congress, so generous in supporting our own forces today, may not support the aid needed for progress in Afghanistan tomorrow.

Obama has a plan for leaving Iraq.  He needs one for leaving Afghanistan too.