Why have European large governing parties lost electoral ground in recent decades? Although most explanations draw on theories of dealignment, this paper advances a novel, institutional, argument by focusing on the role of elections. According to previous research, elections have an impact on political attitudes by fortifying prior partisan affiliations and increasing levels of voters’ information. We posit that voting when the incumbent is particularly unpopular has an effect on political stances and behaviour whose implications are felt over the adult life cycle, increasing vote shares of current opposition parties in the future. This proposition is examined using an instrumental variables approach and taking Spain as case of study. To be more specific, we focus on three general elections (1996, the 2004 and 2011) in which the overall evaluation of the national government was pretty negative and we have incumbents of different ideology (i.e., centre-left in 1996 and 2011, and centre-right in 2004). To empirically examine our hypotheses we need to construct two groups to be compared with respect to their voting choice trajectories: the treatment group consists of those individuals who are barely above 18 in the considered election and are, hence, eligible to vote whereas the control group consists of those individuals that are slightly below the eligibility threshold in that occasion and are, hence, not allowed to vote. We examine the subsequent voting trajectories of these people after the aforementioned election. For example, in 1996 the popularity rates of the incumbent Socialist Party were quite low after 13 years in office. In the paper, we investigate whether citizens that had just turned 18 before that election have been continuously less likely to vote for the Socialist Party in subsequent elections that those that came of age in the months following the election date. Our findings show that being eligible to vote in these three elections decrease support for the then incumbent parties in the immediately next general election. This effect remains in subsequent elections although its magnitude decreases over time. We attribute this impact to the especially strong modifying role that the electoral context plays for young voters.

            In the second part of the paper, we explore the potential comparative lessons of our hypothesis by using the British Election Studies data and seeing whether the hypothesis also applies to the 1979 and 1997 UK general elections with a very unpopular Labour and Conservative government, respectively.