Yet, believe it or not, political scientists, economists, and sociologists have done theoretical and empirical work that is extremely relevant to what is happening in Afghanistan, and that has been quite systematically tested and confronted to evidence. Not that this means they speak the truth or that their conclusions should be given some kind of privileged status in the debate. But what they tell us should at least be part of the discussion: good science says little about what "ought" to be, but it tells us something about what "is," and this should matter.
I have three big contributions in mind: the first has to do with the side effects of aid dependence (Djankov et al., 2007; Easterly, 2007); the second with the side effects of democracy in unstable environments (Bates et al., 2008a; Bates, 2008b); and the third with the limits of state-building in poor states with "difficult geographies" (Herbst, 2000; Rubin, 2002). Their implications for the case of Afghanistan are clear: 1) far too much aid is being given to Afghanistan, twisting the incentives of government officials and local leaders; 2) elections like the one Afghans just went through make their current or potential rulers focus on short term gains, which is bad for long-term peace and economic development; and 3) no centralized rule is possible in Afghanistan, which means that stability cannot come from an hypothetical "victory" of the central government over regional challengers, but from deals with them.
If these insights are valid, and I think they are, much is wrong about the West's current efforts in that country. See below for the references.