In his book Humanitarian Intervention and Legitimacy Wars: Seeking Peace and Justice in the 21st Century, Richard Falk argues that, with the growing prevalence of soft power, historical lessons of asymmetric warfare and legitimacy wars must be taken into account. Falk rejects the realist notion that the state is the only rational actor, offering a more constructivist approach that focuses on the norms, culture and morality of the international community. He asserts that humanitarian intervention is on the decline, and legitimacy wars are increasing. Much of this legitimacy is based on international law and its relevance in the international community.