Coalitions are partnerships among distinct actors that coordinate action in pursuit of shared goals. But what distinguishes them from other kinds of partnerships? The term is widely used to describe joint ventures in a wide range of arenas, most notably in international geopolitics or political party competition and governance. The literature on coalitions is dominated by discussions of war and peace, election campaigns, and parliamentary dynamics. Just as in war or politics, successful collective action in civil society often depends on the formation and survival of coalitions - insofar as the whole is often greater than the sum of the parts.