Case law covers court opinions, but its meaning is often reduced to decisions from appellate courts and courts of last resort. This hierarchy is governed by the principle of stare decisis, which is the principle of subservience to older decisions, and which is briefly described below*:
  • This American legal principle comes from the royal courts of England and was received in the United States. It can be said that the principle of stare decis is what labels a legal system as “common law” and opposes it to the “civil law” system.
  • The hierarchical structure of the U.S. court system has fundamental implications for the degree of authority that precedent commands. The higher in the hierarchy a court is, the larger the scope of its prior decision’s authority is.
  • The principle of stare decisis ensures that past judicial decisions are formally “binding” on factually similar present controversies within the same jurisdiction (a kind of geographical limitation). In other words, when a court has established a principle of law as applicable to a certain state of facts, that court and lower courts will follow that principle in all future cases in which the facts are substantially the same.
  • Thus, the principle of stare decisis gives precedential value to past court decisions within well-established geographical and factual limits.
In order to understand how the principle of stare decisis works, first you need to find the decision in each opinion, and thus segregate the decision or holding of an opinion from its dicta. This is a very demanding and difficult process. But as any process it has its logic which starts with the exercise of "briefing a case." While briefing a case, make sure that you establish each legal issue or question the court has to answer, because for each legal question there is a holding or decision. If it sounds to mechanical, then you need to be aware that this is just a rather simplistic presentation, so when you start briefing cases be prepared for a much more demanding reality.

According to Eva Hanks**, briefing a case is relatively easy, because all cases follow the following structure:
(a) Heading
(b) Facts
(c) Procedural History
(d) Legal Issue(s)
(e) Holding(s) or decision(s)
(f ) Reasoning or dicta
(g) Separate (dissenting) opinions

The doctrine of stare decisis makes possible legal predictions. In other words, case law generates rules that rely on prior decisions within the boundaries established by the doctrine of stare decisis. As the name “case law” suggests, a particular decision, or a collection of decisions, generates law-that is, rules of general application.

Case law is sometimes used as synonym with “common law,” and it covers all judicial decisions that have precedential effect upon later decisions from the same jurisdiction. Sometimes both terms are used to contrast with statutory law-law that is contained in the body of legislative acts. While both at the federal or state level the legislative body has the power to abolish or modify common law as it sees fit, courts have the ultimate say in deciding what a statute is.

Case law is also synonymous with judge-made law. Judges “make” law when they decide a case. This is more apparent when they decide a case that is not exactly controlled by precedent or by a statute—“an issue of first impression”—and less obvious when they apply prior case law. However, either way, it is unavoidable that judges will transplant in their decisions their own understanding of the role of the law, public policy, and the mores of their times. Law is not an “antiseptic product of logic” said Justice Holmes, as it is not a “brooding omnipresence in the sky.” Case law, Justice Holmes explained, is the result of the judges’ understanding of the “necessities of the time, the prevalent moral and political theories, intuitions of public policy, avowed or unconscious, even the prejudices which judges share with their fellow-men.”

Stare decisis wants to control thus human whim both at the legislative and judicial level. Next section will raise some questions about how successfully this principle has been applied to this end.

* For the civil law student, the best analysis of stare decisis can be found in ARTHUR VON MEHREN, THE CIVIL LAW SYSTEM: AN INTRODUCTION TO THE COMPARATIVE STUDY OF LAW (2d ed. 1977).
**EVA H. HANKS ET AL., ELEMENTS OF LAW, 81-92 (1994).