Political scientists researching economic foreign policy have generally taken one of two analytic approaches. The first is based on realpolitik, the traditional application of “high” politics to the “low” politics of economics. This approach considers economics subordinate to politics. The concept of the national interest dominates; the pursuit of power—what enables the state to achieve its goals of security, welfare, and other societal values—is seen to underlie most actions. The study of foreign economic policy is thus an analysis of the distribution of power among states within the international system. By understanding a state's sources of strength and areas of vulnerability in relation to other states, the analyst will better understand the creation of foreign policy. Hans Morgenthau notes that while states may sometimes pursue economic policies for their own sake (in which case they should take little interest in their success), the more important economic policies they will favor are instruments of political power.Stephen Krasner views the state as an autonomously motivated actor, able to guide policy in pursuit of state priorities while resisting interest groups and ideologies. According to this “power theory”, the state tries to increase its economic competitiveness, ensure security of material needs, and promote its broad foreign-policy objectives. Economic policy is for the most part subordinate to and best explained by state priorities and prerogatives. Robert Tucker, Klaus Knorr, Robert Gilpin and others have also adopted this framework.