The Costs of Coalition: Coalition Theories and Italian Governments

Governments in Italy both change and remain the same. From 1946 to 1992 the Christian Democratic Party always held governing power. But almost no cabinet stayed in office more than a few years, and many governments collapsed after only a few months. How can instability coexist with stability in this way? How can governments break up at such low cost and with so little effect on alternation? These questions are rooted in—but not resolved by—the available game-theoretic literature on coalitional behavior. My answer is that politicians' purposive actions can reduce the costs of coalition. I argue that the costs of making, breaking, and maintaining coalitions depend on political institutions and on the array of parties and voters in policy space. Institutional and spatial conditions structure politicians' opportunities and attempts to lower costs. Under some conditions, as I show, coalitions are cheap, and politicians can easily make coalitions even cheaper. The inference is that this framework comprehends both Italy's extremes and the degrees of stability found in other parliamentary democracies.