According to received wisdom parties have played a mainly destructive role in French political development. Of questionable legitimacy, pursuing narrow sectarian goals, often corruptly, they have brought about division, weakness and the collapse of regimes. A proper reading of history suggests differently. By combining historical research and contemporary political science theory about party, the author shows that for over a century party has irrigated French democracy in often invisible ways, brokering working compromises between groups divided strongly along social, political and cultural lines. The key to this success is the party system, which allowed for a high degree of collusion and cooptation between political elites, rhetoric notwithstanding. This hidden logic has persisted to this day despite the advent of presidentialism and remains the key to the continuing prosperity of French democracy.