There are many versions of liberalism, but it would be uncontroversial to say that they agree in placing a premium on individual liberty. As a political paradigm, liberalism is committed to protecting the freedom of persons to live and think as they choose without interference from the state, provided they do no harm to others. This fundamental commitment underlies the classical liberal arguments for religious liberty and toleration articulated by John Locke and J. S. Mill. It forms the basis for legal provisions guaranteeing freedom of religious belief, worship, and expression in liberal democratic nations, as well as the principle of non-establishment, which prohibits the state from favoring any religion or from favoring religion over nonbelief. The formulation of these two principles, religious freedom and nonestablishment, requires that the spheres of the secular and the sacred be distinguished in order to institute a particular relation between them. Questions have been raised about the validity and universality of this distinction, as well as its implications for the place of religion within political life. In contemporary political theory, the topic of public reason has been especially prominent, the point of contention being whether and how religious discourse may be allowed in political reasoning.
Balancing religious freedom against other fundamental liberal rights poses another difficulty in cases where the beliefs and practices of religious individuals and communities come into conflict with general laws or compromise equality, another central liberal value. Sometimes social and political judgments about such cases seem to apply a double standard to the religious practices of certain minorities, moreover, and to reflect an element of cultural racism. This is arguably true of attitudes and decisions in Western countries regarding the hijab and other types of veils worn by Muslim women. Applying liberal principles for regulating religion in a fashion that is genuinely neutral and impartial remains a challenge. Indeed, some argue that there is no way of defining “religion” for the requisite purposes without privileging certain forms of it. If so, liberal efforts to protect religious freedom may end up enforcing varieties of religious establishment.