Chapter Two presents an abbreviated history of judicial review, divided into six time periods. It documents four previous revolutions in constitutional law. The history suggests that future revolutions are almost inevitable. The chapter highlights two broad trends that are supported by empirical data. First, the Supreme Court shifted its primary focus from private law to public law between the late nineteenth century and the mid twentieth century. Second, the type of law that the Court applies to decide public law cases has changed. In the nineteenth century, the Court applied a mix of international law, statutes, and common law – but rarely constitutional law – to decide public law cases. By applying types of law other than constitutional law, the Court was engaging in weak judicial review. Since the Warren Court era, the Court has consistently applied constitutional law in more than 50 percent of public law cases. Application of constitutional law typically involves strong judicial review. When the Court applies constitutional law to decide public law cases, Congress cannot override Supreme Court decisions involving major public policy controversies.