Countervailing power
Countervailing power, or countervailance, is the idea in political theory which suggests that the wielding of power by two or more groups, centers, or sets of interests within a polity can, and often does, yield beneficial effects through productive opposition and containment between opposing forces. As a political concept, it resembles those of agonism, agonistic pluralism, and checks and balances, encapsulated in the often-quoted phrase from Federalist No. 51 that "ambition must be made to counteract ambition". The notion of countervailance has been applied in both politics and economics.