The four most common sources of law include cultural customs, common law, precedent, and legislation. Each culture, country, state, or municipality has its own methods and standards for creating laws. While methodologies and technicalities may differ, the basic law sources are consistent, approaching near universal sourcing standards, no matter the country, cultural history, or political climate. To varying degrees, nearly all governments and other forms of leadership rely on similar sources or combination of sources to establish laws.
Australian law, for example, stems from common law, legislation, and Australia’s constitution. Comparatively, sources of law in Spain include legislation, commonly referred to as the principles of law, as well as cultural customs. In the United States and many European countries, law sources include case law or precedent, legislation, and common law. All law sources in the United States must conform to federal and state constitutional rights and guidelines, ensuring that they serve the greater good of society.
Even the most primitive of societies have sources of law, albeit generally less formalized. Where developed nations use common law, tribal groups and nations rely on customary law. Such laws are based on cultural customs and beliefs regarding acceptable behaviors and practices held by tribal society and its elders. Such laws, whether deemed customary or common law, seldom appear in written form, yet citizens adhere to such rules to the same extent as to written law. In terms of law sources, customs and common law represent the universal source for societal rules across all cultures and countries.
Regarding the most common law sources in civilized society, legislation is a form of formal written law found in virtually every country and municipality worldwide. Legislation includes executive as well as royal decrees, federal and state statutes, enactments, and constitutional authority. In short, legislation is written law enacted by the official governing body of a particular people. Such laws are codified in specific language for use and interpretation by each country’s judicial system.
Finally, although not all governmental bodies use case law or precedent as sources of law, those that do often use case law to establish legitimacy and application of law. When a court of law or other official entity rules on a particular question of law not previously addressed, a precedent is set. Such case law histories provide a documented record whereby common and legislative laws are applied to real situations. As a source of law, precedence and case law serve to establish documented, real world application of a given law.
Considering the life of a single law, each of the four sources of law can be seen as a stage of development. To illustrate, a society may establish proper marrying age through cultural customs. As the society grows and advances, cultural beliefs and practices establish a more formal understanding of proper marrying age, forming the basis of common law. Precedent, meaning leaders make public decisions and thus a public record of such laws, backs up common law and establishes its validity through documentation. Eventually, such laws are written and codified, resulting in legislative law.