A complex liberal version of utilitarianism is introduced which bears similarities to John Stuart Mill's moral and political philosophy and offers a promising approach to liberal democratic theory. Formally, liberal utilitarianism is represented as a type of generalized social welfare functional which maps any given set of individual vector-valued utility functions into a social ordering. The generalized social welfare functional in question relies on the experienced members of society to classify ond compare the different kinds of utilities found in individual vectors; to grant and protect libertarian rights with respect to a well-defined private kind of individual utilities; and to make the interpersonal comparisons required to aggregate over each of the public kinds of individual utilities. At the same time, it is dynamic in that it implicitly comprehends many different levels of a society's moral development from a liberal perspective.
An axiomatization of the ideal liberal utilitarian social welfare functional is provided such that, on the one hand, each person has an absolute right to individual liberty over the issues within his private sphere, and, on the other hand, has an equal voice in a liberty-respecting, strongly monotonk, anonymous and neutral public choice rule operating in a distinct public sphere. The harmony of these private and public components implies the possibility of an ideal liberal democracy.