Recent attempts to weaken constraints of accountability on elected leaders are causing growing concerns about the state of liberal democracy. Yet, the evidence shows that electorates remain largely committed to democratic norms. This paper shows that democratic backsliding can occur even when most voters and most incumbents intrinsically value democracy. Due to voters' reference-dependent preferences, opportunistic authoritarians emerge: against their own liberal tendencies, these leaders choose to challenge norms of democracy (and then partially back down) in order to lower the standards to which voters will hold them. In equilibrium, voters do sanction serious, sudden blows to democratic norms, but electoral incentives do not inoculate against gradual backsliding---in fact, under certain conditions they encourage it. We show that polarization, voter's access to information, and institutional checks and balances all have an ambiguous effect on the occurrence of democratic backsliding.