Ever since the landmark case of Marbury v. Madison (1803) the United States Supreme Court has had the power of judicial review. Judicial review gives it the power to strike down laws it deems unconstitutional. Nevertheless, some judges have shown a marked reluctance to use that power, as they believe that, in some cases, it usurps the prerogative of the democratically-elected Congress.

The starting point of judicial restraint is that all legislative acts must be upheld unless they represent an egregious violation of the Constitution. Beyond that, any changes must only be made by the relevant legislative body, be it state or Federal.

Judicial activism adopts a completely different approach. Activist judges have no qualms about courts making policy to remedy the deficiencies of the Constitution as traditionally interpreted. Or to put it another way, they offer an expansive interpretation of the Constitution in order to fulfill certain social and political goals.

For instance, under Chief Justice Warren, the Supreme Court developed a radical jurisprudence that greatly expanded the rights of the individual. A prime example of this would be the case of Miranda v Arizona (1966), which established that criminal suspects had to be read their constitutional rights before being questioned by law enforcement officers.

Critics argued that the Court in this case was making policy and therefore going beyond the bounds of its authority. However, supporters of judicial activism retorted that such an approach was necessary if the Constitution were to keep up with changes in society.