Make the Effort to Win, Okay?

Strategypage takes a tour of Afghanistan, including air power, the Russians and Iranians, the Pakistanis, and Heroin.

I don't understand why we'd fail to make the extra incremental effort to try to win this war given what we've sunk into it so far, given what happened on 9/11 when enemies ran freely there, and given the amount of effort it would take to re-secure the place if our enemies win again (seek Iraq, if we are lucky enough in Afghanistan not to have a complete collapse if we fail to make the effort in Afghanistan).