In the midst of a severe economic crisis that started in 2008, several European governments and political parties have launched initiatives to reduce the number of deputies in parliament such as in the Netherlands, Portugal, Ireland or Austria. We draw on previous rational choice accounts to electoral system change (Colomer 2005; Boix 1999; Benoit 2001, Strom 1990) and on cartel party theory (Katz and Mair 2002, 2009; Katz) to elaborate a series of hypotheses that allow us to shed light on the elements that trigger the emergence of electoral reform debates and to disentangle the factors that determine the different party strategies.

On the basis of the comparison of the strategies followed by the Spanish Popular Party (PP) in different Autonomous Communities in 2011 and 2012 to reduce the number of subnational legislators, we test whether institutional reform- or the attempts to reform- can be seen as a form of party response to electoral change and uncertainty (Muller 2002). We find that the emergence of the debates seems to be linked to the vested interests the party has in the current system and the openness of the structure of competition.