Morgenthau writes that America has become the foundation of the lawful order of the Western world and the "fountainhead of its culture", but that the country is unaware of it. The author contends that the United States historically developed the idea of its "natural purpose" within the boundaries of the North American continent, referring to US intervention in Central America as "expeditions... in the nature of isolated forays, primarily for defensive purposes"; to the annexation of the Philippines as "a temporary aberration," noting also that the arena within which the United States must defend and promote its purpose has now become world-wide.