In spite of the immense body of work on the electoral costs and benefits of governing for parties, little is known about the potential impact of their presence in parliament. The literature on cartel parties assumes that achieving parliamentary representation, in and of itself, is beneficial for them. However, a direct test on this question is still missing. In this paper, we plan to offer empirical evidence to fill this void by using as case of study the Spanish regional elections. Taking advantage of the discontinuities generated by legal thresholds of representation, we will estimate the causal effect that produces on the success of a small party the fact of having obtained at least one seat in the preceding regional election. Identification is achieved by comparing parties around the area of the threshold, minimizing size-related differences between them this way. Results indicate that parties that slightly clear the threshold in a given regional race improve their fortunes in the future, either in national or sub national elections. Moreover, we demonstrate that the effect also travels in the opposite direction, that is, from the national to the regional level.
