Liberal democracy rests on mental preconditions that have not been adequately reflected in legal theory. Markus Kern develops an interdisciplinary concept of mental integrity that is oriented toward the foundations and conditions of a liberal democracy. In legal and philosophical terms, the psyche is regarded as the epistemic perspective of the subject. This is complemented, from a psychoanalytic point of view, by the unconscious and, from a social-scientific perspective, by the entanglement with social structures. This multi-layered, contextualized subjectivity shapes the configuration of democratic freedom: fundamental rights, democracy, and human dignity are based on mental conditions, particularly in connection with autonomy. Ensuring these implicit prerequisites of the law requires three principles of mental integrity, each in both an individual and a collective dimension: freedom from manipulation, psychosocial well-being, and self-responsibility. They embody protection needs regarding external and internal influences as well as with respect to a self-determined relationship to oneself. At the same time, the protected interest remains open to development. It points more broadly to the need to reflect on hegemonic power structures. Radical democratic analyses, however, show that social emancipation necessarily remains incomplete. In terms of positive law, the author locates mental integrity in the general right of personality (individual), in the principle of democracy (collective), and in the transparency of the process of political will formation (conceptual). What is essential is an ongoing, self-reflective process of securing freedom.