Parties, Legislators, and the Origins of Proportional Representation

The well-known Rokkan hypothesis suggests that the adoption of proportional representation (PR) in many European democracies in the early 1900s came about as a strategic effort by traditional conservative parties to preserve political power after the extension of the franchise and increased industrialization increased the vote base of leftist parties. As this theory treats political parties as unitary actors, it fails to acknowledge the incentives faced by individual legislators. Using roll-call data from six different reform proposals in Norway in 1919, we document considerable within-party variation in the political support for electoral reform: (i) frontbenchers and future cabinet ministers were more likely to vote in favor of adopting PR than backbenchers, and (ii) legislators occupying safe seats in the pre-reform period were less likely to vote in favor.