A court decision is a ruling by a judge in a case. A judge makes a decision by analyzing the facts of the case, the arguments made by the lawyers, and then using law (precedent) that has been established in other cases to decide the outcome of the current case. The decision usually includes how the judge is going to rule in this case and also explains the reason behind the ruling.
When the Supreme Court decides a case, there are often several opinions. The Justices who are assigned to the case will write a majority or principal opinion and any Justices who want to express their views may write a concurring or dissenting opinion. Generally, all of the opinions in a case are published together in a single document. The document is prefaced by a syllabus prepared by the Reporter of Decisions, which summarizes the Court’s decision.
A Justice who writes a concurring or dissenting opinions usually agrees with the outcome of the case but disagrees with how the majority or principal opinion reached that outcome. Dissents sometimes seem like an empty gesture of protest, but some have shaped future Court decisions. Justices who write a majority or principal opinion must be “signed on” to it before the Court will publish it. This means that the Justices have agreed to its contents and are unified on their views. This is not always possible, especially in close cases. Occasionally, Justices who are initially divided over how to rule on a case later switch their votes after reading the drafts of the majority and dissenting opinions.