The spare vote is a version of single transferable voting applied to the ranking of parties, first proposed for elections in Germany in 2013. This preferential party system is a ranked proportional representation electoral system applying to political parties instead of individual candidates. The spare vote refers to a secondary vote (preference) of the voter, which only comes into play if the first preference for the political party preferred by the voter, is below the electoral threshold. In Germany, there were draft laws for the spare vote system in Saarland, Schleswig-Holstein and Brandenburg federal states, but they were not implemented. Under party-list proportional representation with a threshold, the fraction of wasted votes due to the electoral threshold can reach up to 30% and represents a democratic deficit as measured by disproportionality. Despite this, a spare vote is not a feature in any list PR system in use as of this date. The German Federal Constitutional Court ruled that the electoral system is not required to have such a supplementary contingent vote feature. The term "spare vote" not only refers to the additional specification of a second preference but can also mean the electoral system working with a second preference as a whole. Not every second preference is a spare vote. Ranked voting systems differ in terms of their field of application, choice of party lists vs. choice of individuals. In particular, the following ranking procedures should be strictly distinguished from the spare vote: Single transferable vote (and its single winner version instant-runoff voting also called the alternative vote), contingent vote, and supplementary vote: In contrast to the spare vote, which ranks political parties, these systems rank individual candidates. The electoral threshold typical in party-list proportional representation and mixed-member proportional representation causes tactical voting and spoiler effects.
Alexandre Schmid, Yusuf Leblebici, Milos Stanisavljevic