Simplifying Law: What Is Common Law?

Common law is an integral part of the Australian legal system, yet it is often misunderstood. Many people mistakenly believe that so-called ‘judge-made law’ is somehow separate, or even superior, to legislation passed by Parliament. This guide will briefly explain what common law actually is, its history and the differences between common law and civil law systems.

What is Common Law?

In the simplest terms, common law is simply the collection of precedents established by previous cases. This is why it is sometimes called ‘case law’ or ‘judge-made law’. Essentially, this means that if a judge reaches a specific conclusion on a certain set of facts, then for other cases with very similar, or even the same, facts, a court is bound to follow the same conclusion. Of course, it’s not quite this simple. For example, the hierarchy of the court is also important: A lower court is always bound by a higher court’s decision but not vice versa. Consider a decision made by the High Court of Australia. As it is the apex court in Australia currently, all other courts are lower than it, and would therefore be bound by its decisions. However, a decision made by the Victorian Supreme Court, for example, would be binding on the County Court of Victoria and the Magistrates’ Court of Victoria, but not the High Court.

A second important consideration is what conclusion is binding. Now this may seem very silly- if a judge concludes that this person is guilty on these facts, then any other case with the same facts will also have the same outcome, right? Unfortunately, it is not so clear-cut. It is somewhat misleading to say the ‘conclusion’ is binding. Rather, it is the reason for the decision that is binding. It is more commonly known as the ratio of the case, which is short for ratio decidendi, which in turn is Latin for ’the rationale for the decision’. It is very specific but in complex cases, sometimes it is disputed as to what the actual ratio of the case was! This means that lawyers must read the judgments very carefully, and understand exactly how the judge came to their conclusion in order to find the ratio of the case. The ratio of a case can be contrasted with obiter dictum, also known as obiter or obita for the plural, which is Latin for ’that which is said in passing’. As the Latin suggests, an obiter is a remark, observation or opinion made by a judge that is not necessary for the decision. That is to say, the same conclusion could be reached without the obiter. That isn’t to say it’s not important; indeed, the obiter of one case may influence the ratio of another. It just isn’t necessary to reach the particular conclusion and is therefore not binding, generally speaking.¹

What Is Superior: Common Law or Legislation?

The short answer is it’s always going to be the written law. There are many reasons for this, many of which are tied to history. However, one key reason is related to the role of the judiciary in the doctrine of the separation of powers. In short, the separation of powers divides ’the government’ into three branches: the executive branch, the judicial branch and the legislative branch. The idea is that if the power is split, no single entity can over-power the others. Thus, each branch has a unique role. To simplify things, the idea is that the legislative branch (i.e. Parliament), which is democratically elected and controlled, will write the law. The judicial branch, comprised of all the courts, will then ‘interpret’ that written law. The executive branch, which covers a large number of entities, including public servants and defence forces, is then responsible for putting those laws into operation, through enforcement.

Under the separation of powers, it is clear that the role of creating law falls to Parliament. Therefore, no court can create or overrule laws made by Parliament, they can only ‘interpret’ the meaning of the law. What does this mean in practice? Consider this fake law that has just been passed by Parliament and is now enforceable: “No one can sell jelly to a child”. While it may seem straightforward, there are a number of ambiguities. Does ’no one’ apply to individuals as well as corporations? What counts as ‘jelly’? Is any wobbly food jelly? What about a child? Is a child someone under 18 or under 16? These are the questions that the court would have to answer. Then, if Parliament decides that the court’s interpretation is not what they actually meant (e.g. a court decides that ‘child’ is anyone under 16 but Parliament meant anyone under 18), they can simply amend the legislation and the courts would have to follow the new legislation (child is someone under 18), even if, at common law, a child was someone who was under 16. If Parliament does not enact conflicting legislation, then the common law precedent stands.

Why Do We Have a Common Law System? Why Not Civil Law?

So why do we use such a cumbersome system? As with many other things in Australia, the short answer is ‘Britain’. Essentially, Australia just adopted the British legal system, including its common law.² So why did Britain start using the common law? As with many other things in Britain, the short answer is ‘William the Conqueror and 1066’. Following the coronation of William, he began changing the existing Anglo-Saxon ’legal system’ (which was really just a body of rules and punishments at this stage). Throughout the Middle Ages, statutes were developed and the courts’ role and powers began to be fleshed out further. Over time, precedents began to be set, laws were written and powers of courts were consolidated. The Victorian Era saw a ‘modernisation’ of the legal system as well as a re-organisation of the courts’ structure. Going into the 20th century, the areas of public and private law were further developed and in the 21st century, international law became even more prevalent. This is a gross over-simplification of the origins of common law, but it goes to show the the strength, indeed the very foundation, of common law systems, is simply time. The longer a precedent stands without being overturned, the stronger it is as it becomes more ’embedded’ in the legal system.

So with all of this in mind, why didn’t Britain adopt a civil law system like the majority of other countries? Indeed, pretty much all common law systems in the world are former British colonies and everyone else either follows a civil law system or a religious/traditional/customary law system. Well, the short answer is Napoleon and the Romans. Pretty much everyone else decided that it’s easier to write everything down and to follow those ‘codes’ instead of having this big mass of judge-made laws which are interpretations of the written law. These ‘codes’ originally came from the Romans’ Corpus Juris Civilis (‘Body of Civil Law’) and then got modernised by Napoleon in the Napoleonic Code. The code, and variants of it, have since been adopted by the majority of continental Europe, South America and parts of Africa (most of which were former French colonies).

The fundamental difference between civil law systems and common law systems is that a court’s decision is not treated as binding on any other court in a civil law system. Rather, emphasis is placed on the codes as-written. There are some other differences, such as the role that lawyers/judges play (in civil law systems, judges are more inquisitorial whereas in common law systems, the lawyers are adversarial), how the jury works and the rules surrounding evidence, but the main difference is that court precedents are not binding in civil law systems.

Conclusion

In summary, common law is the body of precedents established by past judges’ decisions. Precedents from higher courts are binding upon lower courts. Common law does not overrule written legislation, but rather the judiciary works with the legislative branch in order to create clear and consistent laws.

Banner image credit: Giammarco Boscaro.