What are the common law rules?

Answer 1

Common law is derived from the opinions of prior cases. Common law from higher courts in the the same jurisdiction is usually binding while other jurisdiction's rulings are only persuasive. Common law in the US and commonwealth countries may look as far back as to old cases in English courts. - Learned Foot

Answer 2

Perhaps you mean to ask, "What is common law?"

In the USA, we have different types of laws such as state statutes and federal codes (code of federal regulations). The way a law becomes a law depends on what type of law it is.

COMMON LAW is law that comes from the courts, not from legislation or other governing bodies. Common law is also known as "case law" because the law develops from the case that is before the court.

Because we want to be "fair" and treat similar cases in a similar way, common law sets what is known as a "precedent" by which courts are guided in their decisions.

Each time a case is published by a court, it becomes part of the common law.

The entire body of common law is HUGE, and it is subject to interpretation. When a court interprets common law in a way that is arguably wrong, an attorney files an appeal to a higher court. That court then analyzes the precedential common law along with the facts of the case. When the appellate court issues its written opinion ("an order"), it will either agree with the lower court, disagree with the lower court, or agree in part and disagree in part.