Sequential Voting and Agenda Manipulation: The Case of Forward Looking Tie-Breaking
47 Pages Posted: 21 Aug 2014 Last revised: 16 Oct 2015
Date Written: October 6, 2015
We study the possibilities for agenda manipulation under strategic voting for two prominent sequential voting procedures, the amendment and the successive procedure. We show that a well-known result for tournaments, namely that the successive procedure is (weakly) more manipulable than the amendment procedure at any given preference profile, extends to arbitrary majority quotas. Moreover, our characterizations of the attainable outcomes for arbitrary quotas allow us to compare the possibilities for manipulation across different quotas. It turns out that the simple majority quota maximizes the domain of preference profiles for which neither procedure is manipulable, but at the same time neither the simple majority quota nor any other quota uniformly minimize the scope of manipulation, once this becomes possible. Hence, quite surprisingly, simple majority voting is not necessarily the optimal choice of a society that is concerned about agenda manipulation.
Keywords: Sequential voting, agendas, manipulation
JEL Classification: C72, D02, D71, D72
Suggested Citation: Suggested Citation