Judicial review is increasingly prevalent in modern democratic government. Yet with unelected judges reviewing – and potentially overturning – the work of the people's representatives, it also has long been, in Justice Oliver Wendell Holmes' words, ‘the gravest and most delicate' task that courts undertake. This book establishes a framework to consider the value of judicial review in modern democracy, grouping answers to this question into one of three main arguments, or ‘visions' for judicial review: legalist; rights-protecting; and majoritarian. The strength of these visions is then tested with an original dataset of constitutional court outcomes from four European courts – Poland, Slovenia, the Czech Republic, and Latvia – to determine whether any vision meets its promise. In fact, there is surprising support for the potentially majoritarian benefits of judicial review – a finding that challenges much of our existing theory regarding the value of the courts in modern democracy.