Judicial activism refers to court decisions that arguably go beyond applying and interpreting the law and extend into the realm of changing or creating laws, or going against legal precedents. Arguably, these decisions are made based on the judges' personal philosophies or political affiliations. When a judge makes a court ruling that is not in accordance with constitutional or statutory law or legal precedent, that judge may be said to be "legislating from the bench." When a judge is thought to hold back from being a "judicial activist," he or she may be said to have exercised judicial restraint.
Though the term may be applied to any number of legal and governmental systems in the world, the United States system can be used as an example. In the US, a system of "checks and balances" is imposed to prevent any one of the three branches of the federal government (i.e., the executive branch, the legislative branch, and the judicial branch) from becoming too powerful. Under the separation of powers doctrine, Congress has the power to create laws, whereas the judicial branch is charged with applying the law, and interpreting those parts of the law that might have been drafted in a vague way. Where that line between legal interpretation and creation of the law is, is often a matter of vigorous legal debate. Often, those arguments lie on political lines.
Some might argue, that the Supreme Court's decision in Heller, where the right to bear arms as granted by the Second Amendment was held to be an individual right as opposed to a right meant to be conveyed upon regulated militias, was an activist one. Alternatively, some may argue that the holding in Roe, which made abortion a woman's individual right, went against a strict interpretation of the Constitution, which didn't expressly convey that right. Some rulings that are arguably examples of activism, however, are supported by both liberals and conservatives. The ruling in Brown v. Board of Education which eliminated segregation in public schools, may be one such example.
Judicial activism can exist at virtually any level, including state, federal, and the Supreme Court. Often, when it arises at the Supreme Court level, another legal debate is implicated — the theories of Constitutional interpretation. Originalists, for example, are generally inclined to apply the Constitution strictly, according to the precise terms used by the authors of the document. Non-originalists believe that some interpretation is permissible and that that was in fact the intent of the authors in creating the Constitution as a living document. Depending on which form of Constitutional interpretation one ascribes to will affect how much interpretation is permissible by judges.
