Please don’t vote for me: strategic voting in a natural experiment with perverse incentives

Whether individuals vote strategically is one of the most important questions at the intersection of economics and political science. Exploiting a flaw in the German electoral system by which a party may gain seats by receiving fewer votes, this paper documents patterns of strategic voting in a large, real world election. During the 2005 elections to the Bundestag, the sudden death of a right-wing candidate necessitated a by-election in one electoral district. Knowing the results in all other districts and aware of the paradoxical incentives in place, a substantial fraction of the electorate reacted tactically and either voted for a party other than their most preferred one, or abstained. As a result, the Christian Democratic Union won an additional mandate, extending its narrow lead over the Social Democrats.