Separation of church and state names the constitutional principle that government and religious institutions should operate independently of one another, neither the state establishing or funding a particular religion nor religious authorities directly exercising governmental power, though the principle takes substantially different institutional forms in the countries that hold it.
The United States' First Amendment bars Congress from establishing a religion or prohibiting free religious exercise, a formula Thomas Jefferson famously glossed as building a wall of separation between church and state, language that has shaped American constitutional interpretation without appearing in the constitutional text itself. French laicite, developed through a more actively secularizing tradition culminating in the 1905 law separating church and state, goes further than the American model in restricting religious expression and symbols within state institutions and public schools specifically, reflecting a political history in which the Catholic Church's institutional power was itself a target the revolutionary and republican tradition sought to constrain. India's constitutional secularism differs again, aiming for the state's equal treatment of and, in practice, engagement with multiple religions rather than the state's strict separation from religion as such.