On this morning’s Diane Rehm Show, a caller asserted his preference for a new third party and one of the guests cited the cost associated with creating such a party. This is an ongoing lament in US politics, especially in times of heightened frustration with the political class (such as back in 1992 and the Perot movement). While there is little doubt that there are cost (and legal) barriers to the creation of a third party, they are not the major barriers to a third (or fourth, etc.) party in the United States.
The main barrier is math.
Or, more accurately, the electoral system we use to elect members of legislative bodies in the United States, i.e., we use single member districts with plurality winners (also know as first past the post or FPTP). More directly: each seat is individually contested and the candidate with the most votes wins and as the number of viable candidates compete for those votes the most dispersed the votes become. As such, the most likely winner is the party/candidate that is the largest. The incentive to be a competitive, but losing, third party is small.
A recent example well illustrates the principle: the special election in Hawaii (see the numbers to the right). There we had the equivalent of a multi-party contest for a single seat in a single member district with a plurality winner. There can be little doubt that the majority of the voters had a preference other than the winner (who was first past the post, so to speak). Basically, the introduction of three competitive candidates meant that, by definition, the winner would likely win with less than majority support. It is also a situation in which over the long haul the clear strategic choice for the Hanabusa “party” and the Case “party” would be to work together next time so as to capture the ~58% that they appear to represent. Indeed, that basic point is that this is why we have two parties and not three or more: the incentives are for parties to be as inclusive as possible so as to maximize their vote. This incentive structure is clearly a major reason we have a two party system and this dynamic even has a name in political science: Duverger’s Law: “Plurality rule tends to reduce the number of parties to two, regardless of the number of issue dimensions” (Taageperga and Shugart 1989:65).
Indeed, if what one really wants is multi-party competition, then one needs to promote serious electoral reform that would move the system in a more proportional representation direction that would more broadly represent the more specific interests of the public, whether than be the Tea Party, the Libertarians, the Greens or whomever.
As I noted in an earlier post, my predilection at the moment is to a mixed-member system, such as the one used in Germany and elsewhere that elects half the legislature in single-member districts and half via proportional representation.
A parting comment on this topic: when one mixes a serious third party with FPTP, one gets the UK where a third party can get almost as many votes nationally at the larger parties, but still get the shaft, seat-wise.
References
Taagepera, Rein, and Matthew Søberg Shugart. 1989. Seats and Votes: The Effects and Determinants of Electoral Systems. New Haven, Conn.: Yale University Press.
