Parties and Party Systems

Using the most relevant indicators highlighted by the literature on party systems, such as the indexes of volatility, fragmentation, and ideological polarization in the electoral–parliamentary arena, this chapter analyses the development of the Spanish party system since the transition to democracy. It focuses on the different stages of its development, marked by the two main transformations it has experienced: the first in the 1982 elections with the collapse of the incumbent party, and, after a long phase of stability, the second transformation in 2014/15 with the emergence of two new national parties onto the electoral and parliamentary arena. One of the key questions the chapter addresses is why a party system that had remained quite stable for more than three decades since 1982, preventing newcomers from coming in, finally gave way to a transformation in the mid-2010s.