"One thing to keep in mind is that "the Taliban" don't exist as a single, unitary group; it has become a label of convenience for a multiplicity of groups and movements. The second thing to keep in mind is that the situation in Afghanistan is closer to a multi-party civil war with a lot of foreigners added to the mix. In some ways, there are parallels with the Russian civil war of 1917 - 21 and, politically, with the American Revolution and the establishment of the Tetrachy (~300 ce)
You're confronted with the harsh fact that any 'agreement' is going to be with only the temporarily and apparently (though not necessarily actually) dominant faction who likely will not be able to control all the other factions. That's just the Taliban.

Then extrapolate that to the corrupt (by our standards, not theirs) government, other Ethnicities, Tribes, Clans plus the Drug producers, smuggling gangs etc. No one is in charge there so with whom, precisely would 'we' make a deal. Far more importantly, who there would honor that deal -- not even considering that a 'deal' in western eyes and a deal in Afghan eyes are two different things -- as also is the concept of agreement between Muslim and non-Muslim not being binding...

Consider also that any deal is going to have the moral difficulties that Ron suggests -- plus there's Marc's original point -- it is NOT our call; it's up to the Afghans.

I'll also note that with regard to Marc's first comment to Eden, the solution was to leave the pesky colonies to quarrel among themselves about religion, the economy, the role of women and anything else that could be dreamed up...