A basic starting point of foreign and comparative legal research is determining the overarching legal system a jurisdiction adheres to. A state's legal system is the framework for its government, laws, rules, and more. Understanding the applicable legal system should shape your research strategy.
In Common Law systems, judicial opinions take precedence over other types of laws, including legislation. The United States government and 49 out of 50 states are Common Law jurisdictions. The U.S. inherited its Common Law tradition from the United Kingdom, just like many other former and current British protectorates and colonies.
Some of the key features of Common Law systems are the following:
In Civil Law jurisdictions, the primary source of law is a written code.
Features of a civil law system include:
The two major legal systems in the world are Civil Law and Common Law, but JurisGlobe, a project of the University of Ottawa, identifies five categories of legal systems: Civil law, Common law, Customary law, Muslim law and Mixed law systems.
In Mixed law systems, either two or more systems apply cumulatively or interactively, or different systems are applied depending on the legal issue. For example, Civil law controls property, contracts, and family law in Louisiana, while the Common law principles of jury trials, burdens of proof, and pretrial discovery still operate in the state's criminal law. A legal structure with competing or overlapping legal systems is known as "polycentric law"
It is important to recognize that two jurisdictions with the "same" legal system may still be significantly different in reality. For example, the U.S. and the U.K. are both Common Law jurisdictions, but one has a president and a written Constitution while the other has a monarch, a prime minister, and an unwritten constitution.