According to the Duvergerian theories, only viable parties would be expected to stand for elections alone in the long run, whereas non-viable parties would be thought to join a pre-electoral coalition with another party or to withdraw from competition altogether. However, non-viable political parties throughout the world have been shown to continue presenting candidacies, calling into question the Duvergerian theories. Developing from this apparent paradox, I argue that it is the overlap of electoral arenas that generates opportunities for viable parties to present candidacies in arenas where they are non-viable. Through in-depth interviews with political leaders in Canada and Spain, I show that the overlap of electoral arenas turns the decision to present candidacies when non-viable into the dominant strategy, whereas coalescing or withdrawing becomes the least favoured alternatives. This situation leads to an extra supply of parties competing to what the Duvergerian theories predict.
