Economic theory assumes that all actors are rational, to the extent that certainty can be achieved in the real world. The correlation between rationality and uncertainty is therefore an essential theme in Downs’s application of economic theory to democracy and political behavior. His approach runs coherently through his treatise, and requires the continual assertion of his frame of reference. This is particularly significant because a choice-based study of human political behavior must embrace more cause-and-effect uncertainty than economic theory is required to do. Downs performs a balancing act to show that the principles of economic theory can be applied to rationalize the highly variable and uncertain field of political science. Bringing his economic, empirical background to the study, Downs seeks to embrace uncertainty as a key part of his paradigm rather than as a barrier to achieving one.

Throughout his book, Downs acknowledges that not all people act rationally all the time, that irrational behavior does not always preclude beneficial results, and that no understanding of rationality can inform the ultimate goals of political action. Despite these limits, his argument relies on the premise that a rational voter will seek the best material or ideational benefits possible from a government, and a government will maximize its vote share in order to enjoy the benefits of acquiring and holding office.