The study of governmental structures must be approached with great caution, for political systems having the same kind of legal arrangements and using the same type of governmental machinery often function very differently. A parliament, for example, may be an important and effective part of a political system; or it may be no more than an institutional facade of little practical significance. A constitution may provide the framework within which the political life of a state is conducted; or it may be no more than a piece of paper, its provisions bearing almost no relationship to the facts of political life. Political systems must never be classified in terms of their legal structures alone: the fact that two states have similar constitutions with similar institutional provisions
Peace between nations of widely differing political systems and ideologies, especially between communist and non-communist nations: peaceful coexistence between the U.S. and the Soviet Union
