MMP-elections and the assembly size BY Eivind Stensholt DISCUSSION PAPER Institutt for foretaksøkonomi Department of Business and Management Science FOR 15/2019 ISSN: 1500-4066 October 2019 29.10.2019 MMP-elections and the assembly size Eivind Stensholt,
[email protected] mobile (047) 455 27 129 Norwegian School of Economics, Helleveien 30 5045 Bergen Norway Abstract MMP (Mixed Member Proportional) elections for legislatures have ballots with one vote in a local single seat tally and one vote for a party list in a multi-seat tally. In Germany, the multi-seat tally occasionally violated a Participation axiom. The federal Constitutional Court declared this unconstitutional in 2008. Rules were changed. In 2017, the result was a Bundestag with 709 members, 111 of them in extra-ordinary party seats. The paper considers two remedies against excessive assembly size. One is “faithful accounting” of ballot data in each local tally, another a change from Plurality to a Majority method. For this use, we consider IRV, i.e. Instant Runoff Voting, in combination with a 3- candidate Condorcet method. The mayoral IRV election in Burlington 2009 serves as an example, here in the special context of MMP. Violations of the Participation criterion occur also in the usual Majority methods for single seat elections. The legal adoption of a mathematical axiom from election theory have consequences seen in the context of established impossibility theorems. JEL classification D72 Key words: Mixed Member Proportional, Instant Runoff Voting, Participation criterion, legality, legitimacy, Burlington election 2009. Acknowledgement: Thanks to colleague Dirk Schindler for many and useful conversations! 1 MMP-elections and the assembly size Introduction Surveying elections of legislatures, "New Handbook" (Reynolds & al.