I develop a model analyzing common interests and conflict among four classescapitalists, workers, landlords, and peasants in 19th-century Europeand show that strong class position, based on a high degree of organization and solidarity, may actually be detrimental to the economic and political advantage of that class. This occurs when a strong class is excluded from a major class coalition via coalition formation processes. The reason is that the weak class, if they enjoy bargaining power over even weaker classes within a coalition, may not want to form a coalition with the strong class. I apply the main results to coalition formation and political transitions in 19th-century European society.