The Article examines the wisdom of loyalty oaths as a legal institution in contemporary liberal democracies. First, using comparative analysis the Article highlights the growing global interest in loyalty oaths. Second, based upon historical evidence the Article explores the functions of loyalty oaths and assesses their role. Third, through using legal analysis the Article challenges the validity of loyalty oaths and identifies three fundamental problems related to their content and form: the rule of law, freedom of conscience, and equality.The Article reveals liberal concerns associated with the added value of the duty of “loyalty to the law” (allegiance), as distinct from the duty to “obey the law” (obedience). It presents an ongoing tension between loyalty and liberalism and argues that the more loyalty liberal democracies demand, the less liberal they become. The Article concludes that loyalty oaths yield high costs but have low benefits and suggests that liberal states should abandon them as a legal institution.