Duverger’s Law
It might, however, be premature to conclude that American politicians by their nature fall into only two opposing groups, in contrast to politicians in countries with multiple political parties. As noted earlier, in presidential elections it is the states that determine how they select their electors, and today, virtually all the states2 use single round, “winner take all”, referred to as “plurality voting” popular elections for the entire state to choose their Electors.
Maurice Duverger, a French sociologist in the 1950s, identified the strong tendency that single round plurality voting per district tends to evolve towards two-party systems, whereas a double vote majority (where the top two contenders compete in a second round if there is no initial majority) or proportional representation (where winners are allocated by proportion of the votes) tend to favor multi-party systems.
Duverger points out that plurality voting will often lead to what he called Polarization: concentration to two dominant parties because there is little incentive for new parties to form, since they know that even if they obtain a substantial minority in votes, they have to overcome the virtually impossible hurdle of getting more votes than any other party to obtain an electoral result. A particularly flagrant example of the consequences of “winner take all” single district state elections was the US presidential election of 1992, when Ross Perot, a wealthy Texas businessman, received 19% of the popular vote but was unable to win a single Electoral College vote from any state.
The two-party tendency is reinforced by the fact that voters will often be hesitant to cast a “useless” vote for a party that has no chance to win. Duverger presents the example of an election with 100,000 conservative voters and 80,000 liberal voters where normally the conservative candidate will win. should a person within the conservative faction decide to create a new party, that would split the conservative vote, and unless that new party receives more that 80,000 conservative votes (which would appear unlikely) or less than 20,000 (then why launch it), the launch of the new party will mean each conservative candidate will receive less than 80,000 votes, insuring victory of the opposing liberal party. to avoid such a situation the majority party will do everything it can – and will have a strong argument – to prevent the creation of a new party and to persuade its electorate to avoid “wasting” their vote on any new party.
There have been several cases in us history when a majority party split into two factions, leading to the election of the presidential candidate from the less dominant party, but in each case, the majority quickly regrouped and returned to the two-faction system. the above- mentioned unsuccessful bid by Theodore Roosevelt to win with a new party, leading to Woodrow Wilson’s victory, is a case in point.
Even though there are counter examples in various other countries to Duverger’s Law, in the US “winner take all” political systems, third parties have been completely shut out of national office since 1856; based on this long history, it appears highly unlikely that anyone will break through the domination of the Republican and Democratic Parties.
Why did states choose winner take all elections?
As we saw in chapter 1, the constitution gives the states the right to choose the specific method for selecting Electors. In the earliest elections from 1789, the most widely used method was for the state legislatures to choose electors, with the second most popular method to organize elections per electoral district, with a single winner per district, both of these methods making it possible to spread the electoral votes among several candidates. only a few states initially used a statewide popular vote, limited of course to white males, but as states frequently wanted to favor a presidential candidate from their own state, they quickly understood the advantage of concentrating their votes on a native candidate, naturally encouraging them to adopt a “winner take all” approach. the origin of the us, a federation of autonomous states and the natural rivalry between them meant that as soon as a few states used “winner take all” statewide elections, there was a strong incentive for the others to follow. As shown in the chart below, by 1824, more than half of the states used that system, and nearly all of them had adopted it by 1836.
Methods of Choosing Presidential Electors in the first 13 Presidential Elections3
The same phenomenon favoring the two dominant parties has governed elections to the us senate and house of Representatives. since the second world war, only two of the 535 members of congress have been something other than Republicans or democrats (and one of the two is Bernie Sanders, who identifies as an Independent but virtually always sides with the democrats).
Nevertheless, the us has had and has today many splinter parties, including the libertarian, green and populist parties. Although they have never won a national election, they have occasionally won local elections and have siphoned off votes from the two dominant parties, to often influence national election results.
2 With the exception of two states, Maine and Nebraska, who allocate their electoral votes in part by congressional district, rather than as a single state, but this has never had a notable impact on the presidential election.
3 Chart from “how the electoral college Became winner-take-All”, Devin McCarthy, FairVote, August 21, 2012.
