Law shapes politics, economics, history and society in many ways. It defines relationships among people and between nations, and mediates their interactions. It also serves as a source of moral guidance for socially responsible behavior. It also helps define values and standards for human rights, public safety and business practices. In fact, the concept of Law is so fundamental that it has inspired philosophies, religions and countless academic disciplines.
Often, the term Law is used as an adjective to describe a legal system that is codified, organized and enforced by governments. This is a generalization that is useful, but there are important distinctions between the different types of legal systems in the world.
There are two major types of legal systems: civil and common law. In civil law systems, legislatures codify and consolidate laws into small books that judges can easily interpret and apply. This type of law is found throughout the world.
In contrast, common law systems rely on judges to interpret and create law from precedent. In common law systems, court decisions bind lower courts as well as future judges in similar cases. This principle is known as stare decisis.
Common law systems exist in most of the world, but there are also some purely civil law systems, such as the European Codes adopted by Napoleon and Germany. These systems were developed to encourage trade by creating a single, uniform set of rules that merchants could rely on in all parts of the world.
A third type of legal system is religious law, which is based on the teachings and precepts of a particular religion. For example, Jewish halakha and Islamic Sharia law are both legally binding in some religious communities.
The primary function of law is to serve as a means of establishing and maintaining order in society. In most nation-states (as countries are called in international law), this involves determining who has political power, and thus the authority to make and enforce laws. The power to govern is usually a combination of military might and population numbers, but other factors can contribute to the stability of a state.
A fourth function of law is to provide justice, which is usually achieved by a judiciary that is independent of the executive and legislative branches of government. Judicial independence is especially important in a democracy, where the public expects that judges will be fair and impartial. In some cases, however, a government may fail to serve its citizens effectively and a revolution may be necessary to establish a new political-legal system.