Can constitutional courts help democracy thrive? And can they guarantee justice, a value so commonly associated with judiciaries? Approaching the centenary of the establishment of the first centralized constitutional court and of the well-known debate between Hans Kelsen and Carl Schmitt in the Weimar period on the ‘guardian of the constitution’, the question whether constitutional courts, often with extensive formal powers at their disposal, make a difference to democracy and (the perception of) justice gains relevance. The empirical observations on the attacks on centralized constitutional courts in some countries, such as Hungary and Poland, add a further layer to the discussion and may prompt resignations on the capacity of these institutions to safeguard democracy alongside the Hamiltonian thesis of courts lacking ‘influence over either the sword or the purse.’ Yet, while substantial research was done on explaining the reasons for establishment of constitutional courts and the sources of their authority, the systematic assessment of their actual performance as ‘guardians’ has largely been neglected, limiting the range of available tools to answer such questions as a result. Combining theoretical perspectives on the role of constitutional courts in democracy both from political and legal science, in particular new institutionalist scholarship on the role of ideas in generating political change, as well as empirical examples from selected Central European constitutional courts, this research introduces a novel conceptualization of the constitutional courts’ contribution (or lack thereof) to democracy and (the perception of) justice for the purposes of empirical comparative and case study research. It then applies this conceptualization to discuss how the constitutional courts’ diverse understandings of democracy intertwined with the understandings of justice may enhance or limit their capacities to guard democratic regimes, and—indirectly—the courts themselves.