There is widespread concern among many scholars, media commentators, and policymakers that public trust in political leaders and democratic institutions has eroded over time, within Europe and elsewhere, due to public disaffection with how leaders and institutions perform, generating political instability and polarization, constituting a deep-seated legitimacy crisis for representative democracies. All states require a reservoir of political trust from citizens for voluntary acquiescence with authority, but in Europe such trust is thought as being vital to prevent democratic backsliding. Despite extensive concerns, a considerable scientific debate remains about these common claims, including 1) whether systematic evidence from public opinion trends supports a systematic decline in political trust across European societies; 2) whether any erosion, which is demonstrated to have occurred in specific societies, can be attributed to shortfalls in the policies or procedural performance of governing authorities; 3) whether the consequences of any decline in public trust have indeed triggered greater political instability and polarization; and, finally, 4) on this basis, whether claims of a widespread legitimacy crisis are valid or exaggerated. To address these important issues, TRUEDEM conducts a systematic examination of the patterns, mechanisms, and determinants of political trust in Europe, focusing on the trustworthiness of political actors and institutions as the key driver for trust attitudes. The project’s primary objectives are to develop a rigorously reevaluated theory of political trust and to formulate a comprehensive policy toolkit comprising short- and long-term interventions. These goals are designed to bolster both understanding the informed trust judgements of the public and strengthening the overall trustworthiness of political institutions. TRUEDEM: Trust in European Democracies (2023-2025) is a 3-year collaborative project which has partners in Austria, Czechia, France, Germany, Greece, Italy, Poland, Romania, Slovakia, Slovenia, Sweden, and Ukraine.