The United States is the most important external actor in Latin America. US relations with Latin America seem to be characterized by abrupt changes in US policy, especially in the twentieth century after the rise of the United States to great power status. The US objective to encourage or develop political stability in Latin America derives from the assumption by US leaders that the overall interests of the United States, as a major, industrial, metropolitan, status quo state, are best served in a secure, peaceful, and stable world. The United States has further formulated its Latin American policies on several subregional levels. During the last few years of the nineteenth century, the United States changed its policy orientation from traditional isolationism to a rudimentary internationalism. The United States emerged from World War II as the most powerful nation in the world with involvements on a global scale.