The law of the United States
consists of many levels of codified and uncodified forms of law, of
which the most important is the United States Constitution, the
foundation of the federal government of the United States. The
Constitution sets out the boundaries of federal law, which consists
of constitutional acts of Congress, constitutional treaties
ratified by Congress, constitutional regulations promulgated by the
executive branch, and case law originating from the federal
judiciary
The Constitution and federal
law are the supreme law of the land, thus preempting conflicting
state and territorial laws in the fifty U.S. States and in the
territories. However, the scope of limited federal preemption is,
because the scope of federal power is itself rather limited. In the
unique dual-sovereign system of American Federalism (actually
tripartite because of the presence of Indian reservations), states
are the plenary sovereigns, while the federal sovereign possesses
only the limited supreme authority enumerated in the Constitution.
Indeed, states may grant their citizens broader rights than the
federal Constitution as long as they do not infringe on any federal
constitutional rights. Thus, most U.S. law (especially the actual
"living law" of contract, tort, property, criminal, and family law
experienced by the majority of citizens on a day-to-day basis)
consists primarily of state law, which can and does vary greatly
from one state to the next
At both the federal and
state levels, the law of the United States was originally largely
derived from the common law system of English law, which was in
force at the time of the Revolutionary War. However, U.S. law has
diverged greatly from its English ancestor both in terms of
substance and procedure, and has incorporated a number of civil law
innovations
General
overview
Sources of
law
In the United States, the
law is derived from various sources. These sources are
constitutional law, statutory law, treaties, administrative
regulations, 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 are subordinate to that document. No law
may contradict the Constitution
Constitutionality
Where Congress enacts a
statute that conflicts with the Constitution, the Supreme Court may
find that law unconstitutional and declare it
invalid
Notably, a statute does not
disappear automatically merely because it has been found
unconstitutional; it must be deleted by a subsequent statute. Many
federal and state statutes have remained on the books for decades
after they were ruled to be unconstitutional. However, under the
principle of stare decisis, no sensible lower court will enforce an
unconstitutional statute, and any court that does so will be
reversed by the Supreme Court. Conversely, any court that refuses
to enforce a constitutional statute (where such constitutionality
has been expressly established in prior cases) will risk reversal
by the Supreme Court
American common
law
The United States and most
Commonwealth countries are heirs to the common law legal tradition
of English law. Certain practices traditionally allowed under
English common law were expressly outlawed by the Constitution,
such as bills of attainder[16] and general search
warrants
As common law courts, U.S.
courts have inherited the principle of stare decisis. American
judges, like common law judges elsewhere, not only apply the law,
they also make the law, to the extent that their decisions in the
cases before them become precedent for decisions in future
cases
The actual substance of
English law was formally "received" into the United States in
several ways. First, all U.S. states except Louisiana have enacted
"reception statutes" which generally state that the common law of
England (particularly judge-made law) is the law of the state to
the extent that it is not repugnant to domestic law or indigenous
conditions. Some reception statutes impose a specific cutoff date
for reception, such as the date of a colony's founding, while
others are deliberately vague. Thus, contemporary U.S. courts often
cite pre-Revolution cases when discussing the evolution of an
ancient judge-made common law principle into its modern form, such
as the heightened duty of care traditionally imposed upon common
carriers
Second, a small number of
important British statutes in effect at the time of the Revolution
have been independently reenacted by U.S. states. Two examples that
many lawyers will recognize are the Statute of Frauds (still widely
known in the U.S. by that name) and the Statute of 13 Elizabeth
(the ancestor of the Uniform Fraudulent Transfers Act Such
English statutes are still). Regularly cited in contemporary American
cases interpreting their modern American
descendants
However, it is important to
understand that despite the presence of reception statutes, much of
contemporary American common law has diverged significantly from
English common law. The reason is that 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
Early on, American courts,
even after the Revolution, often did cite contemporary English
cases. This was because appellate decisions from many American
courts were not regularly reported until the mid-19th century;
lawyers and judges, as creatures of habit, used English legal
materials to fill the gap. But citations to English decisions
gradually disappeared during the 19th century as American courts
developed their own principles to resolve the legal problems of the
American people. The number of published volumes of American
reports soared from eighteen in 1810 to over 8000 by 1910 By
1879, one of the delegates to the California constitutional
convention was already complaining: "Now, when we require them to
state the reasons for a decision, we do not mean they shall write a
hundred pages of detail. We [do] not mean that they shall include
the small cases, and impose on the country all this fine judicial
literature, for the Lord knows we have got enough of that
already"
Today, in the words of
Stanford law professor Lawrence Friedman: "American cases rarely
cite foreign materials. Courts occasionally cite a British classic
or two, a famous old case, or a nod to Blackstone; but current
British law almost never gets any mention." Foreign law has never
been cited as binding precedent, but merely as a reflection of the
shared values of Anglo-American civilization or even Western
civilization in general
Levels of
law
Federal
law
Federal law originates with
the Constitution, which gives Congress the power to enact statutes
for certain limited purposes like regulating interstate 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 Federal Register and
codified into the Code of Federal Regulations. Regulations
generally also carry the force of law under the Chevron doctrine.
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
In the beginning, federal
law traditionally focused on areas where there was an express grant
of power to the federal government in the federal Constitution,
like the military, money, foreign affairs (especially international
treaties), tariffs, intellectual property (specifically patents and
copyrights), and mail. Since the start of the 20th century,
aggressive interpretations of the Commerce and Spending Clauses of
the Constitution have enabled federal law to expand into areas like
aviation, telecommunications, railroads, pharmaceuticals,
antitrust, and trademarks. In some areas, like aviation and
railroads, the federal government has developed a comprehensive
scheme that preempts virtually all state law, while in others, like
family law, a relatively small number of federal statutes
(generally covering interstate and international situations
interacts with a much) larger body of state law. In areas like
antitrust, trademark, and employment law, there are powerful laws
at both the federal and state levelsThat coexist with each other.
In a handful of areas like insurance, Congress has enacted laws
expressly refusing to regulate them as long as the states have laws
regulating them (see, e.g., the, McCarran-Ferguson
Act)
Under the doctrine of Erie
Railroad Co. v. Tompkins (1938), there is no general federal common
law. Although federal courts can create federal common law in the
form of case law, such law must be linked one way or another to the
interpretation of a particular federal constitutional provision,
statute, or regulation (which in turn was enacted as part of the
Constitution or after courts lack the). Federal plenary power
possessed by state courts to simply make up law, which the latter
are able to do in the absence of constitutional or statutory
provisions replacing the common law. Only in a few narrow limited
areas, like maritime law, has the Constitution expressly authorized
the continuation of English common law at the federal level
(meaning that in those areas federal courts can continue to make
law as they see fit, subject to the limitations of stare
decisis)
The other major implication
of the Erie doctrine is that federal courts cannot dictate the
content of state law when there is no federal issue (and thus no
federal supremacy issue) in a case. When hearing claims under state
law pursuant to diversity jurisdiction, federal trial courts must
apply the statutory and decisional law of the state in which they
sit, as if they were a court of that state, even if they believe
that the relevant state law is irrational or just bad public
policy. And under Erie, deference is one-way only: state courts are
not bound by federal interpretations of state
law
If this was not confusing
enough, state courts are not bound to follow judicial
interpretations of federal law from the federal courts that sit in
a state, including federal courts of appeals and district courts
(that is, the intermediate appellate courts and trial courts).
There is only one federal court that binds all state courts as to
the interpretation of federal law and the federal Constitution: the
U.S. Supreme Court itself
Federal statutory enactment
and codification
After the President signs a
bill into law (or Congress enacts it over his veto), it is
delivered to the Office of the Federal Register (OFR) of the
National Archives and Records Administration (NARA) where it is
assigned a law number, and prepared for publication as a slip law.
Public laws, but not private laws, are also given legal statutory
citation by the OFR. At the end of each session of Congress, the
slip laws are compiled into bound volumes called the Statutes at
Large, and they are known as session laws. The Statutes at Large
present a chronological arrangement of the laws in the exact order
that they have been enacted
Public laws are incorporated
into the United States Code, which is a codification of all general
and permanent laws of the United States. The main edition is
published every six years by the Office of the Law Revision Counsel
of the House of Representatives, and cumulative supplements are
published annually. The U.S. Code is arranged by subject matter,
and it shows the present status of laws with amendments already
incorporated in the text that have been amended on one or more
occasions
Federal regulatory
promulgation and codification
Congress often enacts
statutes that grant broad rulemaking authority to federal agencies.
Often, Congress is simply too gridlocked to draft detailed statutes
that explain how the agency should react to every possible
situation, or Congress believes the agency's technical specialists
are best equipped to deal with particular fact situations as they
arise. Therefore, federal agencies are authorized to promulgate
regulations. Under the principle of Chevron deference, regulations
normally carry the force of law as long as they are based on a
reasonable interpretation of the relevant
statutes
Regulations are adopted
pursuant to the Administrative Procedure Act. Regulations are first
proposed and published in the Federal Register (FR or Fed. Reg.)
and subject to a public comment period. Eventually, after a period
for public comment and revisions based on comments received, a
final version is published in the Federal Register. The regulations
are codified and incorporated into the Code of Regulations
(Federal CFR which is published once) a year on a rolling
schedule
Besides regulations formally
promulgated under the APA, federal agencies also frequently
promulgate an enormous amount of forms, manuals, policy statements,
letters, and rulings. These documents may be considered by a court
as persuasive authority as to how a particular statute or
regulation may be interpreted, but are not entitled to Chevron
deference
Formulation of federal
precedent
Unlike the States, there is
no plenary reception statute at the federal level that continued
the common law and thereby granted federal courts the power to
formulate legal precedent like their English predecessors. Federal
courts are solely creatures of the federal Constitution and the
federal Judiciary Acts. However, it is universally accepted that
the Founding Fathers of the United States, by vesting "judicial
power" into the Supreme Court and the inferior federal courts in
Article Three of the United States Constitution, thereby vested in
them the implied judicial power of common law courts to formulate
persuasive precedent; this power was widely accepted, understood,
and recognized by the Founding Fathers at the time the Constitution
was ratified. Several legal scholars have argued that the federal
judicial power to decide cases or "controversies" necessarily
includes the power to decide the precedential effect of those cases
and controversies
The difficult question is
whether federal judicial power extends to formulating binding
precedent through strict adherence to the rule of stare decisis.
This is where the act of deciding a case becomes a limited form of
lawmaking in itself, in that an appellate court's rulings will
thereby bind itself and lower courts in future cases (and therefore
also impliedly binds all persons within the court's jurisdiction).
Prior to a major change to federal court rules in 2007, about
one-fifth of federal appellate cases were published and thereby
became binding precedents, while the rest were unpublished and
bound only the parties to each case
As Judge Alex Kozinski has
explained, binding precedent as we know it today simply did not
exist at the time the Constitution was framed. Judicial decisions
were not consistently, accurately, and faithfully reported on both
sides of the Atlantic (reporters often simply rewrote or failed to
publish decisions which they disliked), and the United Kingdom
lacked a coherent court hierarchy prior to the end of the 19th
century. Furthermore, English judges in the eighteenth century
subscribed to now-obsolete natural law theories of law, by which
law was believed to have an existence independent of what
individual judges said. They saw themselves as merely declaring the
law which had always theoretically existed, not making it.
Therefore, a judge could reject another judge's opinion as simply
an incorrect statement of the law, like how scientists regularly
reject each other's conclusions as incorrect statements of the laws
of Science
The contemporary rule of
binding precedent became possible in the U.S. in the nineteenth
century only after the creation of a clear court hierarchy (under
the Judiciary Acts), and the beginning of regular verbatim
publication of U.S. appellate decisions by West Publishing.[41] It
gradually developed case-by-case as an extension of the judiciary's
public policy of effective judicial administration (that is, in
order to efficiently exercise the judicial power.[41] It is
generally justified) today as a matter of public policy, first, as a
matter of fundamental fairness, and second, that in the absence of
case law, it would be completely unworkable for every minor issue
in every legal case to be briefed, argued, and decided from first
principles (such as relevant statutes, constitutional provisions,
and underlying public policies), which in turn would create
hopeless inefficiency, instability, and unpredictability, and
thereby undermine the rule of law
State
law
The fifty American states
are separate sovereigns with their own state constitutions, state
governments, and state courts (including state supreme courts).
They retain plenary power to make laws covering anything not
preempted by the federal Constitution, federal statutes, or
international treaties ratified by the federal Senate. Normally,
state supreme courts are the final interpreters of state
constitutions and state law, unless their interpretation itself
presents a federal issue, in which case a decision may be appealed
to the U.S. Supreme Court by way of a petition for writ of
certiorari
Most cases are litigated in
state courts and involve claims and defenses under state laws. Each
year, only about 280000 civil and criminal cases are heard in
federal courts, as opposed to 27.5 million civil and criminal cases
in state courts (these numbers exclude 858000 federal bankruptcy
cases, and in state courts million, 4.5 domestic, 1.7 million
juvenile, and 55 million traffic cases)
The law of most of the
states is based on the common law of England; the notable exception
is Louisiana, whose civil law is largely based upon French and
Spanish law. The passage of time has led to state courts and
legislatures expanding, overruling, or modifying the common law; as
a result, the laws of any given state invariably differ from the
laws of its sister States
All states have a
legislative branch which enacts state statutes, an executive branch
that promulgates state regulations pursuant to statutory
authorization, and a judicial branch that applies, interprets, and
occasionally overturns both state statutes and regulations, as well
as local ordinances
All 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." Other states
use terms such as "Revised Statutes" or "Compiled Statutes" for
their compilations. 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, to the
extent that the subject matter of the particular statute at issue
was covered by some judge-made principle at 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 usually reflect democratic sentiment as to what the current
law is (though the entire state of the law must always be
ascertained by reviewing case law to determine how judges have
interpreted a particular codified statute)
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
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 theModel 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 to simplify the task of
summarizing the current status of the common law. Instead of
listing long, tedious citations of old cases that may not fit very
well together (in order to invoke the long-established principles
supposedly contained in those cases), or citing a treatise which
may reflect the view of only one or two authors, they can simply
cite a Restatement section (which is supposed to reflect the
consensus of the American legal community) to refer to a particular
common law principle
Local
law
States have delegated
lawmaking powers to thousands of agencies, townships, counties,
cities, and special districts. And all the state constitutions,
statutes and regulations (as well as all the ordinances and
regulations promulgated by local entities) are subject to judicial
interpretation like their federal counterparts
It is common for residents
of major U.S. metropolitan areas to live under six or more layers
of special districts as well as a town or city, and a county or
township (in addition to the federal and state governments). 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
Types of
law
Procedural
law
Traditionally, lawyers
distinguish between procedural law (which controls the procedure
followed by courts and parties to legal cases) and substantive law
(which is what most people think of as law). In turn, procedural
law is divided into criminal procedure and civil
procedure
Criminal
procedure
The law of criminal
procedure in the United States consists of a massive overlay of
federal constitutional case law interwoven with the federal and
state statutes that actually provide the foundation for the
creation and operation of law enforcement agencies and prison
systems as well as the proceedings in criminal trials. Due to the
perennial inability of legislatures in the U.S. to enact statutes
that would actually force law enforcement officers to respect the
constitutional rights of criminal suspects and convicts, the
federal judiciary gradually developed the exclusionary rule as a
method to enforce such rights. In turn, the exclusionary rule
spawned a family of judge-made remedies for the abuse of law
enforcement powers, of which the most famous is the Miranda
warning. The writ of habeas corpus is often used by suspects and
convicts to challenge their detention while the, Civil Rights Act
of 1871 and Bivens actions are used by suspects to recover tort
damages for police brutality
Civil
procedure
The law of civil procedure
governs process in all judicial proceedings involving lawsuits
between private parties. Traditional common law pleading was
replaced by code pleading in 24 states after New York enacted the
Field Code in 1850, and code pleading in turn was subsequently
replaced again in most states by modern notice pleading during the
20th century. The old English division between common law and
equity courts was abolished in the federal courts by the adoption
of the Federal Rules of Civil Procedure in 1938; it has also been
independently abolished by legislative acts in nearly all states.
The Delaware Court of Chancery is the most prominent of the small
number of remaining equity courts
35 states have adopted rules
of civil procedure closely modeled after the FRCP (including rule
numbers). However, in doing so, they had to make some modifications
to account for the fact that state courts have broad general
jurisdiction while federal courts have relatively limited
jurisdiction
New
YorkIllinois,
and, California are the most significant states that have not
adopted the FRCP. Furthermore, both states continue to maintain
their civil procedure laws in the form of codified statutes enacted
by the state legislature, as opposed to court rules promulgated by
the state Supreme Court, on the ground that the latter are
undemocratic. But certain key portions of their civil procedure
laws have been modified by their legislatures to bring them closer
to federal civil procedure
Generally, American civil
procedure has several notable features, including extensive
pretrial discovery, heavy reliance on live testimony obtained at
deposition or elicited in front of a jury, and aggressive pretrial
"law and motion" practice designed to result in a pretrial
disposition (that is, summary judgment) or a settlement. U.S.
courts pioneered the concept of the opt-outclass action, by which
the burden falls on class members to notify the court that they do
not wish to be bound by the judgment, as opposed to opt-in class
actions, where class members must join into the class. Another
unique feature is the so-called American Rule under which parties
generally bear their own attorneys'fees (as opposed to the English
Rule of "loser pays"), though American legislators and courts have
carved out numerous exceptions
Substantive
law
Substantive law comprises
the actual "substance" of the law; that is, the law that defines
legally enforceable rights and duties, and what wrongful acts
amount to violations of those rights and duties. Because
substantive law by definition is enormous, the following summary
briefly covers only a few highlights of each of the major
components of American substantive law
Criminal
law
Criminal law involves the
prosecution by the state of wrongful acts which are considered to
be so serious that they are a breach of the sovereign's peace (and
cannot be deterred or remedied by mere lawsuits between private
parties). Generally, crimes can result in incarceration, but torts
(see below) cannot. The majority of the crimes committed in the
United States are prosecuted and punished at the state level.
Federal criminal law focuses on areas specifically relevant to the
federal government like evading payment of federal income tax, mail
theft, or physical attacks on federal officials, as well as
interstate crimes like drug trafficking and wire
fraud
All states have somewhat
similar laws in regard to "higher crimes" (or felonies), such as
murder and rape, although penalties for these crimes may vary from
state to state. Capital punishment is permitted in some states but
not others. Three strikes laws in certain states impose harsh
penalties on repeat offenders
Some states distinguish
between two levels: felonies and misdemeanors (minor crimes).
Generally, most felony convictions result in lengthy prison
sentences as well as subsequent probation, large fines, and orders
to pay restitution directly to victims; while misdemeanors may lead
to a year or less in jail and a substantial fine. To simplify the
prosecution of traffic violations and other relatively minor
crimes, some States have added a third level, infractions. These
may result in fines and sometimes the loss of one's driver's
license, but no jail time
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, punishments for drunk driving varied greatly prior to
1990. State laws dealing with drug crimes still 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
Contract
law
Contract law covers
obligations established by agreement (express or implied) between
private parties. Generally, contract law in transactions involving
the sale of goods has become highly standardized nationwide as a
result of the widespread adoption of the Uniform Commercial Code.
However, there is still significant diversity in the interpretation
of other kinds of contracts, depending upon the extent to which a
given state has codified its common law of contracts or adopted
portions of the Restatement (Second) of
Contracts
Parties are permitted to
agree to arbitrate disputes arising from their contracts. Under the
Federal Arbitration Act (which has been interpreted to cover all
contracts arising under federal or state law), arbitration clauses
are generally enforceable unless the party resisting arbitration
can show unconscionability or fraud or something else which
undermines the entire contract
Tort
law
Tort law generally covers
any civil action between private parties arising from wrongful acts
which amount to a breach of general obligations imposed by law and
not by contract
Tort law covers the entire
imaginable spectrum of wrongs which humans can inflict upon each
other, and of course, partially overlaps with wrongs also
punishable by criminal law. Although the American Law Institute has
attempted to standardize tort law through the development of
several versions of the Restatement of Torts, many states have
chosen to adopt only certain sections of the Restatements and to
reject others. Thus, because of its immense size and diversity,
American tort law cannot be easily summarized
Notably, the most broadly
influential innovation of 20th century American tort law was the
rule of strict liability for defective products, which originated
with judicial glosses on the law of warranty. In 1963, Roger J.
Traynor of the Supreme Court of California threw away legal
fictions based on warranties and imposed strict liability for
defective products as a matter of public policy in the landmark
case of Greenman v. Yuba Power Products. The American Law Institute
subsequently adopted a slightly different version of the Greenman
rule in Section 402A of the Restatement (Second) of Torts, which
was published in 1964 and was very influential throughout the
United States. Outside the U.S., the rule was adopted by the
European Economic Community in the Product Liability Directive of
July 1985, by Australia in July 1992 and by, Japan in June
1994
By the 1990s, the avalanche
of American cases resulting from Greenman and Section 402A had
become so complicated that another restatement was needed, which
occurred with the 1997 publication of the Restatement (Third) of
Torts: Products Liability
Exceptions
Much of Louisiana law is
derived from French and Spanish civil law, which stems from its
history as a colony of both France and Spain. Puerto Rico, a former
Spanish colony, 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
Furthermore, Puerto Rico is
also unique in that it is the only U.S. jurisdiction in which the
everyday working language of court proceedings, statutes,
regulations, and case law isSpanish. All States, the federal
government, and most territories use American English as their
working language. Some States, such as California, do provide
certain court forms in other languages (Chinese, Korean, Spanish,
Vietnamese) for the convenience of immigrants and naturalized
citizens. But American law as developed through statutes,
regulations, and case law is always in English, attorneys are
expected to take and pass the bar examination in English, judges
hear oral argument, supervise trials, and issue orders from the
bench in English, and testimony and documents originating in other
languages is translated into English before being incorporated into
the official record of a case
Many states in the southwest
that were originally Mexican territory have inherited several
unique features from the civil law that governed when they were
part of Mexico. These states include Arizona, California, Nevada,
New Mexico, and Texas. For example, these states all have a
community property system for the property of married persons
(Idaho, Washington, and Wisconsin have also adopted community
property systems, but they did not inherit them from a previous
civil law system that governed the state Another example of civil
law). Influence in these states can be seen in the California Civil
Code, where 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)
Many of the western states,
including California, Colorado, New Mexico, and Wyoming use a
system of allocating water rights known as the prior appropriation
doctrine, which is derived from Spanish civil law. It should be
noted that each state has modified the doctrine to suit its own
internal conditions and needs