Get Rid of Unanimity Rule: The Superiority of Majority Rules with Veto Power

Abstract

We study unanimous decision making under incomplete information. We argue that unanimous decision rules are not all equivalent. We show that majority rules with veto power are (i) Pareto superior to commonly used unanimous rules and (ii) ex ante efficient in a broad class of situations. We thank the coeditor, Jesse Shapiro, and five anonymous referees. We also thank participants of the

Voting by Simultaneous Vetoes

“…We interpret this as follows: the veto rights are key to ensure coalitional implementation. This is in line with the recent literature on vetoes that underline that voting mechanisms with vetoes have appealing properties (see [4], [3], [5] and [2] among others). We then consider implementation through mechanisms that exhibit No Gains from Cooperation (NGC): in these mechanisms, a coalition has no more veto power than the union of its members, as in the SV mechanisms.…”

Fake News, Voter Overconfidence, and the Quality of Democratic Choice

“…Our paper connects to a larger literature that studies information aggregation in two-alternative decisions (see, e.g., Austen-Smith andBanks, 1996;Duggan and Martinelli, 2001; Martinelli, 2006; Visser and Swank, 2007;Goeree and Yariv, 2011;Bhattacharya 2013;Bouton, Llorente-Saguer, and Malherbe, 2018).…”

Unanimous Implementation: A Case for Approval Mechanisms

“…The first one is the one focusing on strategic voting and, more precisely, on the unanimity rule (see Feddersen and Pesendorfer [1996, 1997, 1998] for classical references in the area and Koriyama and Szentes [2009] and Bouton et al [2016] for recent contributions). The comparison between the current results and the ones in such a literature seems to be 11 The relation between strategy-proofness and Maskin monotonicity has produced a rich literature.…”