Sweden has by order of the Riksdag pledged to continue its military commitment in Afghanistan until at least 2014, as part of ISAF, the International Security Assistance Force. Since 2010 ISAF has adopted a new strategic approach based on the political and military doctrine of counterinsurgency, COIN. This report discusses the key theoretical elements of the COIN doctrine as applied in Afghanistan. Important elements are examined from a general social science perspective and from past experience of counterinsurgency. Knowledge about counterinsurgency has been limited in Sweden. The topic is old but the Swedish armed forces have not participated in any mission similar to ISAF in modern times. The assessment in this report is that the COIN doctrine in certain key respects stands on a fragile basis scientifically. The report address issues as what is meant by legitimacy in the context of building a new state structure and the impact of aid as a way to increased stability. The report also discusses the experiences of past COIN operations.