Politics has been variously described as centrally concerned: (1) with civil government, the state, and public affairs; (2) with human conflict and its resolution; or (3) with the sources and exercise of power. Correspondingly, definitions of economics have generally focused upon: (1) systems of production and exchange; (2) rational behaviour directed towards the maximization of utility through optimal allocation of scarce resources; or (3) the accumulation and distribution of wealth.
However, agreed definitions in the social sciences are not to be held cheaply. Their ill‐defined frontiers allow for periodic incursions and skirmishes. The border between politics and economics is peculiarly open, for the obvious reason that states dispose of substantial material resources while production and exchange can hardly take place without some framework of security. The main varieties of definition nonetheless deserve attention, since they help clarify the grounds on which challenges to the integrity of each discipline have generally been based.
Clearly the two sets of definitions are analogous. The first pair has to do with institutions; the second with means or processes; the third solely with ends. Taking them in turn, it is clear that few students of politics would readily abandon the study of warfare to economists simply because states are resorting to widespread use of mercenaries and contractors. They regard the production of at least this one essential service of the provision of defence as unequivocally public. Conversely, economists spend a great deal of their time studying the competitive behaviour of free rational actors in markets. But many concede that firms are hierarchical organizations within which authority substitutes for voluntary exchange, that contracts can hardly be relied upon without a framework of law backed up by the state, and that extensive command economies have from time to time existed in which the role of the free market was severely constrained. Large firms have been known to use a variety of means, including their influence over states, to compete by raising the costs of their competitors rather than cutting their own. Mercantilist states routinely do the same. But while many economists deplore such market imperfections, few would wish to concede the study of even the most grossly imperfect markets to political scientists. In short, the mixed character of even those institutions which seem archetypically political or economic often turns out on closer examination to call for forms of analysis more often associated with the rival discipline.
Notwithstanding the dominance of rational choice approaches in many university departments of political science, especially in the USA, one of the more plausible lines of argument for those who wish to claim that politics is something more than the study of economics by the innumerate would seem to be to put their trust in irrationality as a defining feature of human social interaction, whether it be expressed in terms of the Thomistic concept of a sphere of practical reason shot through with contingency because of the Fall, the Hobbesian notion of mankind as the only species able to lie, or the Hegelian idea of absolute free will. Naturally, this poses methodological problems. How may the irrational investigate itself rationally, and why indeed might it really wish to? See also political economy.