Balance or Dominance? Party Competition in Congressional Politics

With a pioneering application of probability models in political science, Stokes and Iversen established "the existence of forces restoring party competition." Whatever the margin of victory in a given election, the partisan vote subsequently tends to return to the point of equal division. The authors introduce an expanded test of electoral equilibrium that allows for effects of major realignments and regional differences, using congressional elections since 1828. They find that the vote division gravitates to the mean but that the mean vote, in most periods of American history and in several regions, departs significantly from the point of equal division and in some instances is prone to a pronounced drift. Hence, during much of their lifetime, many Americans do not experience, in congressional elections, party competition that gives the opposition much of a chance to win.