Strategic voting in the 2011 and 2015 Polish Senate elections: Testing Duvergerʼs Law in the second-order elections

Abstract This article tests Duverger’s law through analysis of the Polish Senate elections in 2011 and 2015. These two elections were held under the new first-past-the-post (or single-member plurality) system, which replaced formerly used unlimited vote. The main aim of the article is to test, whether we can confirm the expectations of strategic voting in the context of the so-called second-order elections, as the Polish Parliament is a classical example of the asymmetrical bicameralism, with the secondary role of the upper chamber, the Senate. The results show that the strategic voting was not universal phenomenon under the plurality rule, as indicated by many violations of Duverger’s law. Our research confirmed that the effect of electoral institutions (institutional structure) is contingent and (at the district level) inhibited by country-specific conditions, with potentially strong influence of the second-order character of the Polish Senate elections.