This essay by Kaare Strøm explores the institutional features of parliamentary democracy and proposes two definitions: a minimal and a maximal (or ideal-typical) one. The minimal definition focuses on the simple and indirect nature of parliamentary democracy, where the executive is accountable to a parliamentary majority through a confidence relationship. The maximal definition uses agency theory to understand parliamentary democracy as a regime of delegation and accountability, highlighting the interdependence between the legislature and the executive. Strøm argues that parliamentary democracy is characterized by a single chain of delegation and accountability, with a single principal delegating to a single or multiple non-competing agents, and each agent being accountable to a single principal. This simplicity can lead to administrative efficiency and increased effort from principals and agents, but it also has disadvantages such as ineffective accountability and a lack of transparency. The essay discusses the challenges facing parliamentary democracy, including the decay of screening devices and the problem of diverted accountabilities, and compares it to presidentialism in terms of advantages and disadvantages.This essay by Kaare Strøm explores the institutional features of parliamentary democracy and proposes two definitions: a minimal and a maximal (or ideal-typical) one. The minimal definition focuses on the simple and indirect nature of parliamentary democracy, where the executive is accountable to a parliamentary majority through a confidence relationship. The maximal definition uses agency theory to understand parliamentary democracy as a regime of delegation and accountability, highlighting the interdependence between the legislature and the executive. Strøm argues that parliamentary democracy is characterized by a single chain of delegation and accountability, with a single principal delegating to a single or multiple non-competing agents, and each agent being accountable to a single principal. This simplicity can lead to administrative efficiency and increased effort from principals and agents, but it also has disadvantages such as ineffective accountability and a lack of transparency. The essay discusses the challenges facing parliamentary democracy, including the decay of screening devices and the problem of diverted accountabilities, and compares it to presidentialism in terms of advantages and disadvantages.