The 2011 Portuguese Presidential Elections: Incumbency Advantage in Semi-presidentialism?

The 2011 Portuguese presidential election resulted in a comfortable victory for the incumbent president, Cavaco Silva, an outcome consistent with the notion of substantial incumbency advantages. However, as this article demonstrates, the Portuguese case is part of a broader pattern, with semi-presidentialism in post-war Western Europe generating a considerable pro-incumbency bias in presidential elections. Using the Portuguese elections as a case study, it is found that this advantage derives not only from the direct benefits of holding office, but also from an indirect effect of incumbency on the quality of challengers. In particular, the average quality of challengers is significantly lower in elections with an incumbent than in open-seat contests.