Big discussion in Spain about the "the end of the two-party system". Just for the sake of comparison, here's Portugal. Voting intentions in polls since the 2005 elections, vertical reference lines are election dates. The first figure shows the sum for the two major parties in the system (PS+PSD) while the second shows the sum for the two major parties to the left of PS (BE+CDU). Linear regression lines and LOESS lines (25% bandwidth).