The erosion of checks and balances is one of the defining traits of democratic backsliding. Aspiring autocrats in countries like Poland, Hungary or Israel have weakened the powers of the courts vis-à-vis the executive, and they have usually done so in the name of popular sovereignty. This paper explores the tension between the rule of law and popular sovereignty from the perspective of citizens. Are citizens willing to accept the constraints on popular sovereignty imposed by the rule of law through horizontal accountability mechanisms and judicial independence? Under what circumstances are voters willing to trade off the rule of law for more popular sovereignty? We explore these questions through an original pre-registered observational study in 15 European countries that introduces innovative measurement strategies aimed at evaluating citizens’ views of the democratic trade-off between popular sovereignty and the rule of law. This evidence is complemented with a pre-registered conjoint experiment on judicial review fielded in four of these countries. The results reveal that instrumental considerations and affective polarization are the key factors that make citizens more open to trading off the rule of law for popular sovereignty. This paper contributes to current debates on democratic backsliding by advancing our knowledge about how citizens view the delicate balance between increasingly contested democratic principles such as popular sovereignty and the rule of law.