The purpose of law varies, but it usually has four basic purposes: to maintain the status quo, preserve individual rights, protect minorities from majorities, and create order. Though law is a very important tool for society, not all legal systems meet these goals equally. For example, authoritarian states are notorious for repressing minorities and political opponents. In addition, most countries were colonized by European powers, which often imposed peace on their colonies in the process.
There are many branches of law that are relevant to everyday life in the United States. Contract law, for instance, regulates the exchange of value, which can range from purchasing a bus ticket to trading in options on the derivatives market. Meanwhile, property law focuses on the rights and responsibilities of parties towards tangible and intangible property. In addition, the U.S. judicial system requires that all landowners register their property, including any easements, mortgages, and rental agreements.
In the United States, a constitution establishes separate judicial, legislative, and executive organs. It also usually contains a Bill of Rights, and often provides a means for annulling conflicting laws. In addition, some constitutions deal with the status of international law. And despite its many shortcomings, a constitution may not provide protection from effective usurpation. It is vital to have a legal system that protects the rights of individuals.