Francis Fukuyama in Prospect Magazine:
Modern identity politics springs from a hole in the political theory underlying liberal democracy. That hole is liberalism’s silence about the place and significance of groups. The line of modern political theory that begins with Machiavelli and continues through Hobbes, Locke, Rousseau and the American founding fathers understands the issue of political freedom as one that pits the state against individuals rather than groups.
Modern liberalism arose in good measure in reaction to the wars of religion that raged in Europe following the Reformation. Liberalism established the principle of religious toleration—the idea that religious goals could not be pursued in the public sphere in a way that restricted the religious freedom of other sects or churches.
Freedom, understood not as the freedom of individuals but of cultural or religious or ethnic groups to protect their group identities, was not seen as a central issue by the American founders, perhaps because the new settlers were relatively homogeneous. In the words of John Jay (in the second “Federalist Paper”): “A people descended from the same ancestors, speaking the same language, professing the same religion, attached to the same principles.”
More here.