Yes, the UN should do more in Afghanistan, but they're hamstrung because all the major nations that can back the UN are now putting their resources into NATO. We're seeing a problem in that we're not getting the kind of support in the UN for attention on Afghanistan. They're basically saying NATO is the big player, and since they, including three permanent members of the security council, say they want to handle it through NATO, then you're blocked from a major UN initiative.
I think we should have a different force there. In fact, I think one model would be that NATO does the really tough stuff when necessary and the UN does the easier part in the various provinces.
To answer the question about how to negotiate with people you can't recognize as being Taliban or not, well, it's negotiating with everyone. You try to bring everyone into the big tent. It's actually a loya jirga process, without exclusion. There's no problem with negotiation there; you just have to negotiate with the people you find opposing you.
There are lots of definitions of peacekeeping, and the UN has one very good definition. They're found in textbooks and we teach them in courses. The definition has expanded. It's not what it was when you were doing peacekeeping. The UN has expanded it. It has become more robust. It's becoming more multi-dimensional and able to adapt to complex internal conflicts.