Continuation of the binomial system in Chile

The Chilean opposition has once again blocked a proposal to reform Chile's binomial electoral system, and so the Concertación is trying to lay the blame on presidential candidate Sebastián Piñera, who has said he supports the reform.

The binomial system is a legacy of the dictatorship and has been a bone of contention for years. Congressional districts have two members. Parties (or coalitions) can put up two candidates per district, but to get both seats a party must win over 2/3 of the total district vote. If they win less than that, then the party with the second most votes gets the second seat.

The intent was to protect the political right and ensure it would keep winning seats despite its relatively small size. Since 1990, there have been many studies of its effects.* For example, it can foster party cooperation (because larger coalitions have a better chance at winning both seats) but it also means that party elites carefully pick and choose who should be in a given district, putting the entire process in the hands of only a few party leaders. Further, it shuts out small parties that do not join coalitions.

But the parties of the right have now guaranteed that can continue to analyze the binomial system and suggest reforms for the foreseeable future.


* Peter Siavelis has been writing about this for years--for an analysis plus suggestions of reform, check out his "Electoral Reform Doesn't Matter-or Does It? A Moderate Proportional Representation System for Chile." Revsita de Ciencia Política 26, 1 (2006): 216-225. Patricio Navia has also published a lot on the binomial system--see here for a paper on candidate selection.