For politics. This is a double assumption: states are predominant: and they act as coherent units. Second, realists assume that force is a usable and effective instrument of policy. Other instruments may also be employed, but using or threatening force is the most effective means of wielding power, Third, partly because of their second assumption, realists assume a hierarchy of issues in world politics, headed by questions of military security: the "high politics” of military security dominates the "low politics" of economic and social affairs.