The state should be secular and neutral among beliefs

Secular humanism affirms that the state should be secular and neutral among beliefs: neither establishing nor favouring any religion, and protecting the equal freedom of all citizens to hold and practise their convictions, religious or not. Humanists hold that government should rest on reason and the common good rather than on religious doctrine, and that the separation of religion and state safeguards liberty of conscience for believers and non-believers alike. A neutral state is seen as the fairest arrangement for a society of diverse and competing convictions.

The philosophical case for a neutral state has a long lineage, from John Locke's A Letter Concerning Toleration (1689), though Locke's own argument notably excluded atheists, whom he judged incapable of trustworthy oaths, and Roman Catholics, whom he judged politically loyal to a foreign power, from the toleration he extended to Protestant dissenters. Its clearest modern constitutional embodiment is the Establishment Clause of the United States Bill of Rights (1791), which forbids Congress from establishing a religion, a provision American humanist and secularist organisations have consistently defended and litigated in court, while France's principle of laicite, formalised in its 1905 law separating church and state, represents a stronger and more actively secular constitutional model than the American approach.

This affirmation follows from the humanist commitments to free inquiry and to grounding public life in reason and human welfare, and it descends from Enlightenment arguments for toleration and the separation of church and state. It distinguishes secular humanism from positions that would give a particular religion authority in law and government. Humanists regard state neutrality not as hostility to religion but as the condition for equal freedom, and the principle is presented here as one that its adherents hold. American constitutional practice around this principle shifted markedly in 2022.

Since Lemon v. Kurtzman (1971), US courts had generally applied the so-called Lemon test, asking whether a government action had a secular purpose, neither advanced nor inhibited religion, and avoided excessive entanglement with it. In Kennedy v. Bremerton School District (2022), a 6 to 3 Supreme Court majority abandoned that framework, holding it "abstract" and "ahistorical," and directed lower courts instead to interpret the Establishment Clause by reference to historical practices and understandings from the founding era; humanist and secularist organisations generally regard the change as weakening the constitutional wall of separation, while the decision's supporters argue it corrects decades of an overly restrictive and doctrinally incoherent standard.