For many decades, stability and predictability were the defining features of German party competition. Throughout the 1960s and 1970s, West German politics was dominated by the well-known two-and-a-half party system, which later expanded with the rise of the Greens in the 1980s and the addition of the PDS (Party of Democratic Socialism) after German reunification.1 Despite the expanding party system, party competition continued to be anchored by the CDU/CSU (Christian Democratic Union/Christian Social Union) on the center-right and the SPD (Social Democratic Party) on the center-left, such that government coalitions at the federal and state level could typically be formed by two coalition partners, while ideologically coherent coalitions among parties on the left or the right were the norm.