Issues of State complicity arise ever more frequently in international relations. Rules which deal with the responsibility of States for aiding or assisting in the commission of internationally wrongful acts by other States are, however, not yet fully developed. States frequently support each other's actions without necessarily considering the potential implications of the rules on complicity in international law. This leads to another problem: is support given to another State automatically to be seen as relevant practice for the development of new customary rules or the interpretation of treaties through subsequent practice? Or is it possible for complicit States to play two different roles: to assist in some conduct while not endorsing the legal claim associated with it? This contribution aims to untangle the various facets of complicit State behaviour. It will argue that in some cases, States can indeed play two different roles. States should, however, be careful in considering the long-term implications of such behaviour.