What are the circuits of law? I hear all the time that something is in the 5th circuit or the 1st circuit of [INSERT STATE HERE]. What exactly are the different circuits? How is law applicable based on the circuit?
A "circuit court" is a kind of court in a judicial system. It generally covers a large-ish area; the name comes from the fact that back in the days of horseback travel, judges would literally ride around a circuit to hold court. The exact meaning depends on the court system. At the federal level, the circuit courts are the main federal appeals courts. Each one covers multiple states (except the DC Circuit which just covers DC and the Federal Circuit which has subject-based jurisdiction). A circuit court normally hears cases before a 3-judge panel; that panel's decision is normally binding precedent in federal courts throughout the circuit, including on future panels of the same circuit. Panel decisions can be overturned by SCOTUS or by the circuit court sitting en banc (i.e. all the judges hear the case, not just 3 of them). Outside the circuit, a circuit court's decision is only persuasive precedent. At the state level, what circuit courts do depends on the state. In many states that have them, they're the most important trial courts, handling large civil cases and felony criminal cases. Some states have lower-tier courts to handle minor issues, in which case they might allow an appeal from the lower courts to the circuit court. This appeal might be like a normal appeal (where the higher court looks at the record from the lower court and only considers whether the lower court got the law wrong), or might be a trial de novo (where the higher court throws out the lower court's decision entirely and tries the case itself from scratch). It really depends on the state. If a state's circuit courts are trial courts, they generally don't set much of a precedent.
Both civil law and common law have civil codes, so that isn't the difference. It is common in civil law jurisdictions for these to be called civil codes and consolidated into the great big book of law. In common law jurisdictions, the civil code is scattered through legislation, regulation, administrative and case law and often not consolidated although, each piece of legislation typically deals with only one (or a related number) of topics. Adversarial vs Inquisitorial In a common law jurisdiction, the role of the judge/jury is to decide the dispute that the parties have brought to the court based solely on the arguments and evidence that they make. A judge who seeks their own evidence or decides the case based on a law the parties have not argued is making a mistake. The judge is free to say to the parties "But what about xyz law?" and let them make an argument about that but they would be denying the parties natural justice if they decided the case on xyz law if that law was not argued. In civil law jurisdiction, the role of the judge/jury is to find out the truth. They have inquisitorial power and decide the case based on all the evidence, the law that was argued and their own knowledge of the law. Precedence In common law jurisdictions, the cases decided by the courts are just as much the law of the land as the acts passed by parliament. When a court hands down a decision on a certain fact pattern, then all courts lower in the hierarchy must make the same decision when presented by a similar fact pattern. These are binding precedents. In addition, decisions of same level or lower courts (where not actually the ones being appealed) as well as decisions in "parallel" jurisdictions are persuasive precedents. A parallel jurisdiction is anything where the law is close enough that it makes sense to use it: Australian courts will tend to look first to other Australian states, then to England &amp; Wales, Canada, New Zealand and other Commonwealth countries then the United States of America and then to civil law jurisdictions. There is nothing nativist in this, it is just that these are the jurisdictions where the laws are "closest" to one another: partly because the courts have historically done this (which tends to lock the common law together), partly because there has been governmental will in creating harmonized laws in Australia (i.e. enacted in each state and territory but essentially the same law - often word for word) and partly because parliaments, when drafting legislation, nick ideas from other parliaments. If the Supreme Court of Western Australia has made a decision on a similar fact pattern under a similar law, a District Court judge in New South Wales had better have some damn good reasons for deciding this case differently but they wouldn't automatically be wrong if they did. However, if the precedent had been set in the Supreme Court of New South Wales than the District Court judge would be wrong to decide differently. Naturally, a lot of argument in common law courts is about why the facts of this case are sufficiently similar/distinct that the precedent should/shouldn't apply. Also, common law judgments emphasize the reasoning that led the judge from the evidence to the conclusion and include detailed analysis of the case each party presented - this is because they need to be understandable to a wide audience. Court hierarchy can be quite complex, this is the one for NSW, Australia: In a civil law jurisdiction, courts are not bound by the rules of precedence - each judgement is a first principles analysis of the facts and the law. This is not to say that civil law judges do not use other judgments in their analysis but they are not required to do so. Broadly speaking, the common law approach promotes consistency, the civil law approach promotes individualized justice.
Under United States copyright law, according to the Copyright Office, 206.01 Edicts of government. Edicts of government, such as judicial opinions, administrative rulings, legislative enactments, public ordinances, and similar official legal documents are not copyrightable for reasons of public policy. This applies to such works whether they are Federal, State, or local as well as to those of foreign governments. Referencing laws is even clearer: copyright doesn't protect referring to something like "Section 830 of the Penal Code of the State of California." Note that this is assuming that they remain within the US, where copyright law is a federal issue. Other countries don't all have the edict of government rule. If a place were to legally secede and become their own country, they would cease to be bound by US copyright law. They would get to decide if it was legal for them to do it or not; this is just like how it works between the UK and US (the UK claims copyright on its laws, but US courts will not enforce that copyright because it's incompatible with US law). Treaties complicate things, but the Berne Convention allows the edict of government exception. That said, seceding from the US unilaterally is both legally and practically impossible; seceding from a state is likewise generally going to be legally and practically impossible without permission from the state. So, it all depends on the agreements made. EDIT: To specifically address the model codes issue, Veeck v. S. Bldg. Code Congress Int’l, 293 F.3d 791 (5th Cir. 2002) was a case specifically about what happens when model codes are adopted wholesale into law. The Fifth Circuit (after initially finding that the model codes were protected) reversed en banc, finding that a model code produced for the purpose of being incorporated into law, and which has been incorporated into law, and which is then reproduced as the law of the place that incorporated it into law, is not subject to copyright. Veeck may not apply to cases where the law merely references the model code, or where the thing in question was not made to be incorporated into law (e.g. state laws referencing the Red Book valuation of a car didn't make the Red Book public domain). If both of those are true, it probably doesn't apply; if one holds but not the other, it's unclear. However, if the actual municipal code directly contains the text of the model code, and you reprint it as the law of that municipality (rather than as the model code), there is no copyright in the law.
"Precedent" refers to a finding of what the law is. A jury only finds facts, and operates (supposedly) within the meaning of the law as already established. All the jury reports is "yes" and "no" to questions of fact (with some reference to existing law): they do not report, at least in any official way "we interpret the law as saying X". So it would be impossible for a jury to "set precedent" in the case law sense. In a notorious case, they might "set precedent" in inspiring other jurors to act similarly, but this is not enforceable precedent in the way that case law precedent is. In the US, if the jury acquits the defendant, that is the end of the matter and there is no re-trial. As for the UK, I am not sure but I think that the prosecution being unhappy with the jury's decision does not create an exception to the double jeopardy rule.
It is certainly possible for the same action to break multiple laws, and be chargeable as multiple crimes. For example, shooting and killing someone may be assault, assault with a deadly weapon, and murder all at the same time. For a different example a person who simply omits to file an income tax return may be guilty of both failure to file a required return, and failure to pay tax due, and in some cases failure to par required estimated tax due as well. For yet another example, driving well above the speed limit may be a violation of the speed limit law, and also careless driving, and possibly also reckless driving. In the first case the assault etc may be lesser included offenses in the charge of murder. That means that they are automatically available to a jury (or judge) trying the accused, who can convict on one of the lesser included charges if they do not convict on the primary count. For the more general case, I don't know of any special term for the situation. It is not usual to have law A which says "do not do X", and also law B which says "you must follow law A". There is no general principle against having such redundant laws, nor is there, in the US, any Constitutional rule against such laws. But legislatures do not normally bother to enact such redundant laws. Laws which will sometimes overlap in their coverage, but in some cases do not overlap are common.
The alternative is the same whether just one lower court or many lower courts ignore SCOTUS precedent. An aggrieved parts will appeal the lower court ruling, and the matter will work its way up the ladder until SCOTUS directly rules on this application of the law. This sort of happens all the time, when lower courts don't apply the ostensive "final ruling" because they find that there is some other overriding consideration ("that rule only applies to businesses employing more than 50 people"). Where the case to be remanded to lower courts for further proceedings consistent with SCOTUS opinion and still the lower courts refuse to comply, i.e open rebellion, SCOTUS could rule that non-compliance by lower courts constitutes contempt, and an order could be issued for the removal (in some form) of offending parties (we may presume, the justices of the lower court). The statute outlining court power allows on order of imprisonment for "disobedience or resistance to its lawful writ, process, order, rule, decree, or command". Federal marshals would then arrest non-compliant judges, unless the marshals too are in open rebellion. If the judges in question were federal judges, the marshals would have to decide whether to obey the order of SCOTUS vs. the order of the district or circuit court. Since under the US Constitution states that "The judicial Power of the United States, shall be vested in one supreme Court, and in such inferior Courts as the Congress may from time to time ordain and establish", it is objectively established that SCOTUS rulings are superior, so provided that the marshals elect to uphold their oath of office, they will enforce the SCOTUS ruling. However, citizen action becomes irrelevant once SCOTUS has made its ruling, and the matter has moved from legal determination of fact to enforcement of established fact.
An "inquisitorial" system is one where the Judge or Magistrate actively questions the accused and witnesses to attempt to determine the facts. The Judge may also determine, at least in part, what witnesses to call in what order. An "adversarial" system is one in which each side presents its case, and the judge acts as an umpire deciding on procedure, and possibly makes the final ruling (or directs a jury to do so) but is not actively involved in questioning witnesses or deciding what witnesses to call. I don't see anything which would prevent a common-law jurisdiction from establishing an "inquisitorial" system by statute except longstanding tradition, but as far as i know no such jurisdiction has ever had such a system in place for dealing with criminal matters. The informal procedures in some small claims courts do have judges more actively involved than in other courts. I think this is also true in some family courts as well. I think I have heard of some civil-law jurisdictions which use something like an adversary system, but i am not sure of that. Certainly a civil-law country could pass a law setting up such a system if it chose to.
All Four of them! Double Jeopardy is not in play if a jurisdiction can lay claim to your criminal action, so if you stand on the Four Corners and shoot a man in any of the four states, each state has a right to charge murder. In addition, the Federal Government can have a go at you because you crossed state lines while in comission of a crime. Plus the Navajo Nation, which controls the reservation land the border is on. So that six separate charges. That said, the state the dead body occupied at time of Murder would have the best case for action and the other three would likely let that state try you first. The Feds would only step in if each of the four states failed to convict, though they can step in whenever they want (they are just watching to see if you'll serve time first). Not sure at which point Tribal jurisdiction applies, but given that this is a fairly common Jurisdiction issue, I'm sure it's been worked out.