The United States, until just before the end of the World War II, excluded itself to a form of isolationism. By doing this, the United States relied on and looked after itself when dealing with foreign policy. But soon after World War II things changed, isolationism could not work for the betterment of the United States any longer. The United States needed to change the way it operated on an international scale, and take on a more demanding role in its foreign policy making. To understand this shift from isolationism to collective foreign diplomacy, an evaluation of the three levels of analysis would present three different aspects on how and why the United States made this shift. When looking at the post-war era, the United States' change from isolationism was essential to its survival due to two key elements: the shift in great power, and the strengthening of United States' military and capitalist economy. By using the three levels of analysis, you will be able to understand in depth how their interaction lead to the United States straying from its traditional isolationism, to its current role of collective foreign diplomacy.
             To understand the entire realm of things, you would need to start from the third level of analysis, "The System." From the post-war International system to the events that lead up to the United States shift, all started at the third level of analysis. Prior to the great wars, the international system consisted of multiple great powers, and in turn caused multiple points of conflict (known as dyads), causing the United State to form its pre-war stance of isolationism to protect its own security.
             After World War II, the fall of Hitler and the devastation suffered during the wars by most of the great powers in Europe, caused the International system to have a shift in great powers. From this shift, it lead to a bipolar system, leaving the United States and a rebuilding communist S...