Interest groups ratings have long been used by social scientists to distinguish between liberal and conservative members of Congress. It is also well known that ratings by different groups are highly correlated with one another. Here, rather than focusing on the similarities between such...

We combine Duverger’s Law (1954) with Demsetz’s (1968) theory of natural monopoly to provide a novel perspective on electoral competitiveness in a single member district, plurality rule system. In the framework we develop, competitiveness depends on the contestability of elections, which...