Reading the latest news from Afghanistan - or at least NZ's contribution to the war in Afghanistan - it is clear that the rationale for the NZ presence is simply political, i.e. Broaden the support for the war as widely as possible by involving as many countries as possible.
Is that a problem? No, not if you mind perceptions (as opposed to facts) driving decision-making. But herein is the essence of public policy making in the West. No respect for facts.