On Political Duopolies: floodgates and antitrust.

American political life has evolved into a nearly perfect duopoly. Even in places and states where the explicit rules allow so-called ‘third party access’ [reflect on that term for a moment], the great variety in these rules has become a costly barrier to entry. In addition, often the rules give explicit advantage to the two main parties and penalize independents. The Wikipedia page on “Ballot access in the 2024 United States presidential election” makes for very sober reading, and then multiply the issues diagnosed there for each major election (at the state or local level).

It’s important to realize — despite Duverger's so-called law — duopoly is not a property of first past the post systems. Most of these are capable of supporting multi-party systems (as we see in many (former) Commonwealth countries), even though the number of major parties will be fewer than in a proportional presentation system.

In addition, the parties can run their primaries more or less as they see fit, and these, in turn, can involve very different voting rules (from a caucus all the way to a state convention). Within/among the fringes of the Democratic party there is non-trivial dissatisfaction about the party’s quite visible tendency to put a finger on the scales and deploy the rules against (what we may call) ‘systemic change’ candidates. As regular readers know, I am myself not a fan of open primaries, but the weaponizing of internal rules is not a sign of an especially healthy democratic culture. Given the comparatively low turn-out rates among American voters, it is not too far-fetched to claim that the duopoly does not cater to all political preferences out there.

I want to make two fairly tentative observations on this state of affairs. First, one notable dis-analogy between political competition and market competition, is that there has been no effort to develop anti-trust techniques to be applied in political life. Obviously, the legislative incentives — dominated as they are by the duopoly — are not promising, but courts and bureaucracies have not been especially pro-active on this front either. (We also lack good measures/metrics for competitiveness in political arena.) The latter is prima facie puzzling because it looks like election law shows favoritism to some citizens who have more effective rights in being represented than others. But I leave that point to civil rights lawyers.

Second, in economics, relatively standard models of duopolies have a tendency to show lots of stability alternated by discontinues jumps in prices/quantity or technological change (etc.)* We seem to witness an analogy to this phenomenon in duo-political regimes. The phenomenon is sometimes called a re-alignment after a generation or two, or a political earthquake. By contrast, in systems of relatively pure proportional representation these changes tend to be smoothed over a number of elections, when coalition partners start to shift and the center of gravity of a parliament moves clearly in one direction (rather than alternating among enduring blocks.)

Another way to put this is that duopolies tend to act like dams on change, before the floodgates open. Perhaps because I grew up in the lowest of lowlands (or because I am over 50), but I have an instinctive distrust of being caught in a possible tidal wave.+

*I thank Ali M. Khan and David M. Levy for discussion.

+these thoughts were prompted by the feedback and questions after a session on a draft paper I co-authored with Nick Cowen and Aris Trantidis at the PPE seminar at GMU.