A novel brand of laissez-faire that lay outside the political mainstream in the early postwar years was broadly hailed at the dawn of the twenty-first century as the common sense of a global age. Yet how to understand neoliberalism as a specifically political thing, especially in the unlikely terrains of Western European and leftist politics, is unclear. This article mobilizes field theory to conceptualize and investigate neoliberal politics in Western democracies, treating the left-right axis as a variable but fundamental organizing dichotomy over which mainstream political parties exert a unique definitional influence. To trace how this dichotomy has shifted over time, I develop a novel index of political neoliberalism using data on the electoral programs of mainstream parties across 22 Organisation for Economic Co-operation and Development countries between 1945 and 2004. I find that between the 1970s and 2004 a revised political center emerged, featuring a new concept of state responsibility and the means by which it should govern: a historical shift that took root across the left-right spectrum among mainstream parties and that was as much in evidence in Continental, Nordic, and southern countries as in Anglo-liberal countries. The overall trend can be fairly characterized as the rise of a specifically neoliberal politics. I suggest that a full explanation requires both a political sociology and a sociology of knowledge, attending to the organizational and cultural bases of Western party systems.