Condorcet Method, Independence of Irrelevant Alternatives, and the Size of the Bundestag

Abstract

ABSTRACT How should an excessively large parliament be effectively reduced in size without violating constitutional principles? This is a question that the German Bundestag has discussed since the introduction of the 2013 electoral reform measure. Facing a Bundestag consisting of 709 members and some public dissatisfaction, a reform measure to decrease the parliament’s size was adopted in 2020. However, the 20 Bundestag, elected in September 2021, again increased in size to 735 members. The newly adopted electoral law still uses plurality voting to select the directly elected lawmakers. It is widely known that selection using the plurality rule is flawed because it violates the principle of majority decision. Aside from this aspect, this paper demonstrates that the plurality rule itself contributes to the excessive size of the parliament. By removing the flaws caused by the plurality rule and replacing this voting scheme with a Condorcet method (simple-majority rule), the targeted reduction of the size of the Bundestag can be achieved.