Duverger's Law

Blog 7

            According to Duverger’s law, it states that the effective number of parties in any electoral district is a function of electoral rules; and more specifically proportional representation allows for more than two effective parties while a single member party district only allows for two parties. Therefore in the case of Brazil, this law holds true to the functions of elections.                                                           In Brazil’s latest election in 2010, as stated in the Inter-Parliamentary Union, there were all 513 seats of the Chamber of Deputies at stake and no one party reserved a majority¹. As follows, using the formula for effective number of parties, the effective number of parties derived was 9.90. This upholds Duverger’s law in that in a proportional system of representation, there is a greater number of effective parties. In Brazil a Presidential system is practiced with proportional representation in the Deputies of Chambers. According to the Kellogg Institute, the electoral process follows that in the Chamber of Deputies, the district magnitudes range from 8 to 60 deputies based on population, which allows for a disproportional representation of states in a PR system. The state that holds the highest number of seats is Sao Paolo with the highest population, and as follows, to gain a seat in the district, the minimum threshold is quite low. The Institute states that the minimum threshold in any district is the electoral quotient- the number of votes divided by number of seats. Therefore in Sao Paolo for example, the party would have to ear 1/60 of the votes². In addition to the threshold and magnitude, Brazil practices a preferential system of casting votes by way of list structure; as well as the largest remainders method of allocating seats in which the highest averages get the seats ². However, even with Brazil’s coherence to the rule of Duverger’s law, which allows for a multiple party representation, there is still an unequal representation because of the low minimal threshold and largest remainders method, there is still a disproportional representation in the system of distributing seats among the states; which means that areas with poverty and lower population are grossly underrepresented.

Works Cited

1. Inter-Parliamentary Union. “Brazil: Chamber of Deputies,.” Accessed November 2, 2012. online. http://www.ipu.org/parline-e/reports/2043_B.htm.

2. Mainwaring, Scott. Kellogg Institute. “POLITICIANS, PARTIES AND ELECTORAL SYSTEMS: BRAZIL IN COMPARATIVE PERSPECTIVE.” Accessed November 2, 2012. Online. http://kellogg.nd.edu/publications/workingpapers/WPS/141.pdf