What is Duverger’s Law?

Most people know it as the observation that plurality elections in single-seat districts tend to come with just two parties. Except that the correlation is weak. As for causation, see Riker (1982):

The direction one must go, I believe, is to turn attention away from the expected utility calculus of the individual voter and to the expected utility calculus of the politician and other more substantial participants in the system. The groups and individuals who buy access and the politicians who buy a future have substantial interests, and it is their actions to maximize expected utility that have the effect of maintaining the two-party system under plurality voting.


So the answer to the question of failure is that third parties are rejected in the rational calculus of expected utility especially by leaders, though also in the calculus by many simple voters. Any adequate theory to subsume Duverger’s law must, I believe, begin there, which is a task for scholars in the next decade.

Back to the future: ‘nonpartisan’ proportional representation

Yesterday, I received an email from the Open Primaries organization. It included the following words. What’s interesting is the suggestion that proportional representation (PR) be designed to cater to independents. Independent-politics reformers typically oppose PR, and PR supporters typically have party proportionality in mind.

There is an accelerating conversation about electoral reform happening. Proportional representation, ranked choice voting, nonpartisan and open primaries, nonpartisan redistricting (and more) are all hot topics.

We’re particularly interested in conversations, campaigns and activities that bridge the gap between structural reform and rising independence. For reform to be maximally effective it needs to be grounded completely in where the American people are and where they are headed.

And they are going independent!

Chapter 3 of More Parties or No Parties documents a similar fusion at the height of the Progressive Era. It didn’t end well!

Superb article on primary reform

By Kyle Sammin for Real Clear Pennsylvania. The piece is all about replacing primaries with nomination-by-convention — a proposal that many political scientists likely would support. Here are my favorite lines:

Progressive–Era reformers thought they were returning power to the people by letting states interfere in party business. Instead, they wound up confusing the people, making them think of primary elections as a “first round” that precedes the general election. Returning to a convention system would let parties be parties again, help party members reach consensus instead of shouting past one another, and enable a party collectively to affirm its vision in choosing candidates who share its values.

And if you don’t like a party’s vision? Start your own party.

Also note the list of countries mentioned in the article. Several of them are frequently held up as examples of ranked-choice voting.

Minor parties also use conventions to select their candidates; so does nearly every political party around the world. Rather than spending taxpayer money on an election that benefits only themselves, the parties must pay their own way. And they do! In Canada, Britain, Ireland, Australia, and nearly any other democracy you can think of, this is how a party’s nominees are chosen.

This piece interestingly was written by a conservative.