Still standing for elections? Political externalities and the determinants of party entry decisions

According to the Duvergerian theories, only political parties expecting to achieve representation are predicted to stand for elections alone in the long run. However, the
empirical evidence shows that throughout the world parties continue presenting candidacies when they are non-viable, thus calling into question Duverger. Developing from this apparent paradox, I argue that the overlap of electoral arenas generates two fundamental opportunities for parties to compete. Through in-depth interviews with political leaders in Canada and Spain, I show that parties take advantage of the existence of economies of scale to present candidacies in non-viable arenas and, most relevant, by presenting candidacies where they are not expecting to become viable they obtain political externalities. Overall, the overlap of electoral arenas turns the decision to present candidacies when non-viable into the dominant strategy, whereas coalescing or withdrawing become least favoured alternatives.