Precedent is an earlier case that is relevant to a case to be decided. If there is nothing to distinguish the circumstances of the current case from the already-decided one, the earlier holding is considered binding on the court. Authority can be either mandatory or persuasive. Mandatory authority is law that is binding on the court deciding the case. A case is only a precedent as to a particular set of facts and the precise legal issue decided in light of those facts. If the case is not a precedent, but contains an excellent analysis of the legal issues and provides guidance for a court, it is a persuasive authority.
Before using any legal authority to analyse a problem, you must know how that authority has been treated by later actions of a court, legislature, or agency. A case may have been reversed or overruled; a statute or regulation may have been amended or repealed.
When you read a statute, you must also read the cases that have interpreted the statute because the wording may be ambiguous. Concurrences and dissents are also very important. You need to read them carefully. To understand why, you need to appreciate that law is man-made.
Disagreement between the majority opinion and concurring or dissenting opinions often frames the key issue raised by the case; to understand the case, you need to understand the arguments offered in concurring and dissenting opinions.
Learning to ‘think like a lawyer’ often means learning to think like a judge, which means learning how to evaluate which rules and explanations are strong and which are weak.
