The law of the United States was originally largely derived from the common law of the system of English law, which was in force at the time of the Revolutionary War. However, the supreme law of the land is the United States Constitution and, under the Constitution's Supremacy Clause, laws enacted by Congress and treaties to which the U.S. is a party. These form the basis for federal laws under the federal constitution in the United States, circumscribing the boundaries of the jurisdiction of federal law and the laws in the fifty U.S. states and territories.
 General overview
 Sources of law
In the United States, the law is derived from four sources. These four sources are constitutional law, administrative law, statutes, and the common law (which includes case law). The most important source of law is the United States Constitution. All other law falls under, and is subordinate to, that document. No law may contradict the United States Constitution. For example, if Congress passes a statute that conflicts with the constitution, the Supreme Court may find that law unconstitutional, and strike it down.
 American common law
The United States and most Commonwealth countries are heirs to the common law legal tradition of English law; for example, U.S. courts have inherited the principle of stare decisis. A small number of important British statutes in effect at the time of the Revolution have been independently enacted in nearly identical form by U.S. states. Two examples that many lawyers will recognize are the Statute of Frauds and the Statute of 13 Elizabeth. Such English statutes are still regularly cited in contemporary legal writings about their modern American descendants.
Although the courts of the various Commonwealth nations are often influenced by each other's rulings, American courts rarely follow post-Revolution Commonwealth rulings unless there is no American ruling on point, the facts and law at issue are nearly identical, and the reasoning is strongly persuasive. The earliest American cases, even after the Revolution, often did cite contemporary British cases, but such citations gradually disappeared during the 19th century as American courts developed their own principles to resolve the legal problems of the American people. Today, the vast majority of American legal citations are to domestic cases. Sometimes, courts, and casebook editors, do make exceptions for opinions on issues of first impression by brilliant British jurists, like William Blackstone or Lord Denning.
Some adherents of originalism and strict constructionism such as Justice Antonin Scalia of the United States Supreme Court argue that American courts should never look for guidance to post-Revolution cases from legal systems outside of the United States, regardless of whether the reasoning is persuasive, with the sole exception of cases interpreting international treaties to which the United States is a signatory. This position follows inevitably from the philosophy of originalism, which posits not only that the Constitution is the ultimate source of judicial authority in the U.S., but that the only proper analysis of the document consists of discerning the "original intent" of its drafters. Therefore, discussion of British law that post-dated the Constitution is irrelevant as it sheds no light on the drafters' intent. Others, such as Justices Anthony Kennedy and Stephen Breyer, disagree, and cite foreign law from time to time, where they believe it is persuasive, useful or helpful.
 Federal law
Federal law in the United States originates with the Constitution, which gives Congress the power to enact statutes for certain limited purposes like regulating commerce. Nearly all statutes have been codified in the United States Code. Many statutes give executive branch agencies the power to create regulations, which are published in the Code of Federal Regulations and also carry the force of law. Many lawsuits turn on the meaning of a federal statute or regulation, and judicial interpretations of such meaning carry legal force under the principle of stare decisis.
 State law
The fifty American states are separate sovereigns with their own constitutions and retain plenary power to make laws covering anything not preempted by the federal Constitution or federal statutes. Nearly all states started with the same British common law base (Louisiana law began with, and has always been strongly influenced by, the French Napoleonic Code), but the passage of time has resulted in enormous diversity in the laws of the states. State courts have expanded the old common law rules in different directions (through their traditional power to make law under the doctrine of stare decisis), and state legislatures passed various statutes expanding or overriding many judge-made laws.
Unlike other common law jurisdictions, all American states have codified some or all of their statutory law into legal codes. Codification was an idea borrowed from the civil law through the efforts of American lawyer David Dudley Field. New York's codes are known as "Laws." California and Texas simply call them "Codes." Most other states use terms such as "Revised Statutes" or "Compiled Statutes" for their codes. California, New York, and Texas have separate subject-specific codes, while all other states and the federal government use a single code divided into numbered titles.
In some states, codification is often treated as a mere restatement of the common law. Judges are free to liberally interpret the codes unless and until their interpretations are specifically overridden by the legislature. In other states, there is a tradition of strict adherence to the plain text of the codes.
The advantage of codification is that once the state legislature becomes accustomed to writing new laws as amendments to an existing code, the code will often reflect democratic sentiment as to what the current law is.
In contrast, in jurisdictions with uncodified statutes, like the United Kingdom, determining what the law is can be a more difficult process. One has to trace back to the earliest relevant Act of Parliament, and then identify all later Acts which amended the earlier Act, or which directly overrode it. For example, when the UK decided to create a Supreme Court of the United Kingdom, lawmakers had to identify every single Act referring to the House of Lords that was still good law, and then amend all of those laws to refer to the Supreme Court.
 Criminal law
In the arena of criminal law, all states have somewhat similar laws in regard to "higher crimes," such as murder and rape, although penalties for these crimes may vary from state to state. Additionally, state laws dealing with drug crimes vary widely, with some states treating possession of small amounts of drugs as a misdemeanor offense or as a medical issue and others categorizing the same offense as a serious felony.
However, for public welfare offenses where the state is punishing merely risky (as opposed to injurious) behavior, there is significant diversity across the various states. For example, the laws controlling drunk driving were rather unstandardized prior to the 1990s.
 Tort law
United States tort law for personal injury tends to vary widely across the states. For example, a few jurisdictions allow actions for negligent infliction of emotional distress even in the absence of physical injury to the plaintiff, but most do not. With practically any tort, there is a "majority rule" adhered to by most states, and one or more "minority rules."
 Attempts at "uniform" laws
Efforts by various organizations to create "uniform" state laws have been only partially successful. The two leading organizations are the American Law Institute (ALI) and the National Conference of Commissioners on Uniform State Laws (NCCUSL). The most successful and influential uniform laws are the Uniform Commercial Code (a joint ALI-NCCUSL project) and the Model Penal Code (from ALI).
Apart from model codes, the American Law Institute has also created Restatements of the Law which are widely used by lawyers and judges as substitutes for long, tedious citations of old cases (in order to invoke the long-established principles contained in those cases).
 Local law
Law affects every aspect of American life, including parking lots. Note the citations to statutes on the sign.
States have delegated lawmaking powers to a staggering number of agencies, counties, cities, and special districts. And all the state constitutions, statutes and regulations are subject to judicial interpretation like their federal counterparts.
Thus, at any given time, the average American citizen is subject to the rules and regulations of several dozen different agencies at the federal, state, and local levels, depending upon one's current location and behavior.
 Odd exceptions
Unlike the rest of the country, as noted above, state law in Louisiana is based on the Napoleonic Code, inherited from its time as a French colony. Puerto Rico is also a civil law jurisdiction of the United States. However, the criminal law of both jurisdictions has been necessarily modified by common law influences and the supremacy of the federal Constitution.
California is a common law jurisdiction with a few features borrowed from the civil law. Besides the codification noted above, it has a community property system for the property of married persons. Also, the California Civil Code shows civil law influences in that the law of contracts is treated as part of the law of obligations (though the rules actually codified are clearly derived from the common law).
 See also
Acts and Codes
 External links
- ^ Elizabeth Gaspar Brown, "Frontier Justice: Wayne County 1796-1836," in Essays in Nineteenth-Century American Legal History, ed. Wythe Holt, 676-703 (Westport, CT: Greenwood Press, 1976): 686. Between 1808 and 1828, the briefs filed in court cases in the Territory of Michigan changed from a complete reliance on English sources of law to an increasing reliance on citations to American sources.
- ^ California is the supreme example of this position. Li v. Yellow Cab, 13 Cal. 3d 804 (1975).
- ^ Constitutional Reform Act 2005, via Office of Public Sector Information (OPSI.Gov.uk)
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