Constitutional review is the power of a body, usually a court, to assess whether law or government action complies with the constitution. Originating in the American constitutional order, it has spread all over the world and is now a ubiquitous feature of government: nearly threequarters of constitutions in force provide for it, a number which includes many non-democracies (Ginsburg and Versteeg 2014; 590). There is no doubt that the phenomenon is important, as it has made judges the final arbiters over issues that used to be exclusively political in nature (Tate and Vallinder 1995: 5; Stone-Sweet 2000; Angell et al. 2005; Hirschl 2004).
Yet, the sweeping diffusion of the institution of judicial review belies substantial variation in how judicial review is structured and exercise. For the most part, the literature approaches the comparisons of judicial review through the lens of three canonical models, associated with the (i) United States, (ii) Germany and, (iii) France respectively. These were the models on offer during the Third Wave of democracy, when many countries rewrote constitutions to include the institution. They remain the classical starting point for a comparative account of judicial review.
Relying on models is a useful way to conduct a comparative inquiry. In the constitutional context, we think of a model as any configuration of institutional features that tend to co-occur, either by convention or by internal logic, and that may provide a basis on which other jurisdictions develop institutional designs. But models are also in part a construction of researchers, who need to decide which feature(s) to emphasize. The canonical models rely heavily on two features; specialization and whether review is abstract and concrete.
In this Chapter, we argue that there are alternative dimensions of variation in judicial review: (i) access, (ii) finality, and (iii) concentration. Relying on these features produces different classifications that cut across the three canonical models. What is more, we argue that some of these features may be more relevant to the practice of judicial review than concentration. We do not ultimately argue that one or the other approach is better: our goal is to show that multiple classifications are possible. We further reflect on the increasing importance of supranational review and how it affects each of the dimensions of access, finality and concentration.
The remainder of this Chapter is organized as follows. We will start by discussing the classical triad; the models of judicial review associated with the United States, Germany and French respectively. We then then propose alternative classifications. We next describe how supranational review can influence those dimensions. We conclude by reflecting upon the relative importance of each of these dimensions.