Practically, what prevents judges from ignoring precedent? This question/answer suggests that the United States' adherence to the common law system is traditional and not mandated by the constitution or federal statute. This makes me wonder what exactly keeps common law alive. I imagine many judges follow precedent because they have a personal respect for tradition or the merits of the common law system. But I also imagine many judges would want to ignore precedent to enact their own opinions. So what prevents such judges from doing so? Are there local or state laws that require them to follow precedent? Can ignoring precedent get them fired? Or do they just fear backlash from the public or their peers if they break tradition? Or is the premise of my question flawed and judges break precedent all the time?
Decisions that break with precedent do happen with some regularity, but far &quot;from all the time&quot; in the US. When they do happen, they are generally only at the top level of a state or federal court system, that is a State supreme Court (or equivalent, some states use a different term) or the US Supreme Court. There are several factors which discourage judges from simply ignoring precedent. First of all, all the training a lawyer receives teaches him or her to respect precedent, and to find rules by examining past cases. precedent is literally the stuff with which a lawyer works, rather more than the wording of statutes (although those are also important). Secondly, as a lawyer works as a litigator, judges will usually ground their decisions on precedents, particularly in appellate cases, explaining their decisions largely in terms of how they conform to or extend precedents. Thirdly, if a lower court judge fails to follow precedent, that judge will often be criticized by an appellate judge or justice, often in the course of an opinion overturning the lower-court judge's ruling. This does not feel pleasant to such a judge. Fourthly, decision that fail to follow precedent are often (although not always) criticized by legal scholars, particularly in law review articles and treatises. Fifthly, lower-court judges who often fail to follow precedents, are less likely to be recommended by senior judges for promotion to appellate positions. However, the actual appointments are controlled by politicians (in most cases) not other judges, so this factor may not be as strong it it would first seem. Only once a judge gets to the level of the Supreme Court of a state, or the Federal Supreme Court, is that judge (now a Justice) expected to alter precedents as needed, and most justices have said that they make such changes only reluctantly. I am not aware of any US state or federal statute or regulation that specifically;y requires judges to follow precedent. The most common way to alter precedent is not to overrule or ignore it, but to distinguish a prior case. This happens when a judge says something like: In the previous case of A v B when had situation X which lead to outcome Q. But in this current case we have the very different situation X1. In the case of X1, the outcome should be S instead of Q. If the new case becomes persuasive the old case A v B may apply to only one specific set of facts that almost never comes up, and the new rule apply to almost all other possible situations. The old case may cease to be cited or applied without ever being formally overruled. And, of course, where the rule is statutory, it may be changed if the legislature alters the law. If the rule is constitutional, it may be changed by a constitutional amendment. For example the 1830s case Barron v Baltimore held that the US bill of rights did not apply to the states, only to the Federal Government. But after the 1868 14th amendment, courts started to incorporate much of the bill of rights into the Due process clause of the 14th, and apply it against the states. This took place gradually, mostly during the period starting with 1898, up until about 1970, but with some incorporation coming as late as 2010 (Heller)
It is binding precedent for lower federal courts in the Ninth Circuit. They are required to follow it. It is persuasive precedent for the other circuits and for state courts. They may be persuaded by the reasoning and will consider the fact that the Ninth Circuit held as it did to be one factor in their decision-making, but they can make a different decision if they want to. Some courts are also more persuasive than others, although this is usually not explicitly acknowledged in written opinions. For example, state courts in the Ninth Circuit are likely to give more weight to a Ninth Circuit opinion than they are to give weight to a decision from another circuit. Cases from the Second Circuit are more likely to be persuasive than cases from other circuits, because of its reputation. Cases from the Southern District of New York are more likely to be persuasive than cases from most other non-local District Courts. There is also a personal reputation function that comes into play when looking at persuasive decisions. Some judges have a better reputation or a better reputation with a particular other judge, and their decisions may be considered more carefully. This is not explicit, but it means a good lawyer will mention the judge's name when a case in support of his position was decided by a well-regarded judge. Finally, the Ninth Circuit's holding would be persuasive precedent for the Supreme Court. You could write law review articles about this, but to dip one toe in: they may be persuaded by the reasoning and it matters to their function of providing unifying law, so especially during the process of applying for a writ of certiorari, they will care what different circuits have held on an issue and which circuits are going which way. But they are not bound by the circuit courts, and will overturn all of the circuits if they think that's the right decision. They did that a while ago with a statute about what it meant to use a firearm while committing a crime, for example.
Finding Certainty There is only one way for certain: Do the supposedly unlawful thing Get sued (civil) or prosecuted (criminal) Go to court - if you win it wan't illegal If you lose, appeal to the next appellate court in the chain In one of those courts refuses to hear your appeal - it was illegal Repeat as necessary until you reach the Supreme Court - if you win it wan't illegal If you lose or the Supreme Court refuses to hear your appeal - it was illegal. Of course, this whole cycle will take a few years and quite a lot of money. Not certain but persuasive Consult a lawyer: their area of expertise is knowing what the law is and how it will likely apply to your circumstances. Of course, they can be wrong about this because - see above. Why is this so hard? Common law jurisdictions, of which Florida is an example, do not have a "Code of Laws" where you can look things up and see if they are legal or illegal. The Common Law in Florida is partially enacted law (by the US, Florida, County, City and finally your housing corporation) and partially unenacted law (decisions made by courts about both the enacted and unenacted law). In fact, enacted law is usually quite ambiguous until it has a body of unenacted (or case) law that surrounds it and provides guidance on how the courts will interpret it. Part of a lawyers skill is knowing (within their area of expertise) what the relevant case and statute law is with respect to the specific facts of the case, or knowing how to research them. Publish and be damned! You can always take the Duke of Wellingtons approach. In common law jurisdictions, everything is legal unless there is a law (enacted or unenacted) that makes it otherwise. If you do not believe that the action you wish to take is illegal then advise the other party that you will give them 24 hours to come back with a court injunction to prohibit it, otherwise you will proceed. You can't call a bluff harder than this!
Courts have inherent jurisdiction to reconsider/recall their own decisions. This rarely happens (especially if the decision has already been &quot;sealed&quot; i.e. issued in writing) but still possible. The principle of finality only applies to parties asking courts to reconsider; it does not constrain courts themselves. So, in this example, &quot;the judge agrees to vacate them&quot; but that decision hasn't been sealed yet. The judge can easily just change their mind (although, again, it rarely happens). No double jeopardy applies because it is still the same trial.
While the answer by Jen does a good job explaining why some possible alternative structures for US courts of appeal (circuit courts) would be unworkable, the real reason why we have such courts is their historical origin. In the United states, Justices of the Supreme Court regularly traveled through the country. They would stop at particular locations, and hold court together with the local judge of a district court as a two-judge court. Appeals from district court decisions were heard. Some were passed along to the full Supreme Court, particularly ones in which the Justice did not agree with the judge. Each Justice had a route, or &quot;circuit&quot; which that Justice covered once or twice a year on horseback (or by carriage) spending half or more of his time &quot;riding circuit&quot;. The process was quite onerous, and was by far the larger part of the work of a Justice. It allowed decisions to be reviewed by a Supreme Court member at places physically closer to the original trials, and served as a filter on cases to be decided by the full court. This practice was derived from the older English practice of having Justices in Iter (later known as circuit judges) who traveled through the country, judging cases that had been held awaiting their arrival. (The word &quot;Iter&quot; is related to &quot;Itinerary&quot;, the list of places one is scheduled to visit.) The Marshall Court and Cultural Change, 1815-1835 by G. Edward White (ISBN 978-0195070590) includes a detailed description of the process of circuit riding during the period of 1815-1835, and the way in which proceeding in the circuit courts influenced constitutional jurisprudence and how cases came to the Supreme Court. I recommend this extensive book for better understanding of the origins of many features of the US Judicial system. Some years after the US Civil war the Circuit Courts officially became the Courts of Appeals and Supreme Court justices stopped &quot;riding circuit&quot;, but the geographical divisions continued to be called &quot;circuits&quot;, and each circuit is still supervised by a single Justice, who rules on &quot;emergency&quot; applications, often for stays of judgement, or for injunctions. The division of the US court system into circuits thus is due as much to historical inertia as to careful design, although an alternate design that was an improvement would not be easy to create.
These situations do come up (and incidentally, this is nothing new, it has been a difficult and recurring legal issue since at least the 18th century), and they really suck to be in, and often there aren't easy answers. There are a lot of legal doctrines out there that are designed to avoid a hard clash of conflicting court orders and to prevent someone from suffering contempt of court sanctions when they are in this bind. Generally, litigants caught in this bind look for these outs. For example, when particular property or records are at issue, often the person in question will "interplead" the property placing it in the jurisdiction of a court to resolve and out of their hands. There is a doctrine called in custodia legis which provides that once something is in the custody of a court that another court may not exercise jurisdiction over it. The entire sub-field of civil procedure pertaining to jurisdiction and venue is designed to avoid these conflicts. U.S. law has a whole sub-field a statutes and legal doctrines like the Rooker-Feldman doctrine designed to prevent these conflicts from coming up when they arise between federal and state courts. One of the most important legal doctrines is that a person cannot be punished for contempt of court for failing to do something that the person being held in contempt of court does not have the ability to do. One argument, which doesn't always work, is that once you are subject to a legally binding court order that has been served upon you that you may not legally defy that court order in order to follow the order of a court which cannot override the decisions of the court issuing the first order. Usually, contempt citations are directed at individual employees or agents rather than at entities. For example, in a dispute over Indian Trust Funds against the United States government, contempt citations were brought against the Secretary of Interior personally and could have sent that individual to jail for not complying. One way the an individual can get out of the order relating to an employment or professional duty is to resign from office and thus deprive oneself of the ability to perform the order. But, the short answer is that there is no one simple legal rule for resolving these situations, and the litigants stuck in these situations look for every available legal argument to resolve it until it is resolved.
Judges do not decide, jurors do (however, if a judge is the fact-finder, then the judge makes such a determination). The main input that the decision-maker gets is a jury instruction. In order to unify "reasonable doubt", "reasonable price", "reasonable delay" and so on, appeal is often made a mythical being, "the reasonable man", so reasonable force would be the degree of force the reasonable man would use in a given situation. I will draw from California criminal instructions ('cuz I have them) but similar instructions can be found across jurisdictions. For example, one instructions says "A natural and probable consequence is one that a reasonable person would know is likely to happen if nothing unusual intervenes". Or from a negligence instruction "A reasonable person would have known that acting in that way would create such a risk". More detailed appeal to The Reasonable Person is found in the justified homicide instruction: Defendant’s belief must have been reasonable and (he/she) must have acted only because of that belief. The defendant is only entitled to use that amount of force that a reasonable person would believe is necessary in the same situation. If the defendant used more force than was reasonable, the [attempted] killing was not justified. When deciding whether the defendant’s beliefs were reasonable, consider all the circumstances as they were known to and appeared to the defendant and consider what a reasonable person in a similar situation with similar knowledge would have believed. If the defendant’s beliefs were reasonable, the danger does not need to have actually existed. The defendant’s belief that (he/she/ [or] someone else) was threatened may be reasonable even if (he/she) relied on information that was not true. However, the defendant must actually and reasonably have believed that the information was true. There is no explanation of what it means to be "a reasonable person". Since nobody believes that they themselves are unreasonable, a simple and also wrong way of judging the matter is to subjectively judge whether you yourself would do the same thing, if you were in that situation. Very often, instructions do not even bother to say what "reasonable" means, so (re interpreting expert testimony) "You may disregard any opinion that you find unbelievable, unreasonable, or unsupported by the evidence"; (re corpus delicti) "That other evidence may be slight and need only be enough to support a reasonable inference that a crime was committed"; "Also, before you may rely on circumstantial evidence to find the defendant guilty, you must be convinced that the only reasonable conclusion supported by the circumstantial evidence is that the defendant is guilty", "when considering circumstantial evidence, you must accept only reasonable conclusions and reject any that are unreasonable" The closest the law has come to articulating an objective characterization of "reasonableness" is in "reasonable doubt" instructions. One characterization is in People v. Feldman, 71 N.E. 2d 433. It is not a doubt based upon sympathy or a whim or prejudice or bias or a caprice, or a sentimentality, or upon a reluctance of a weak-kneed, timid, jellyfish of a juror who is seeking to avoid the performance of a disagreeable duty, namely, to convict another human being of the commission of a serious crime A somewhat improved characterization is the Calcrim instruction Proof beyond a reasonable doubt is proof that leaves you with an abiding conviction that the charge is true. The evidence need not eliminate all possible doubt because everything in life is open to some possible or imaginary doubt There is room for improvement, but it points in the right direction. On rare occasions, a law is written that actually includes a definition. The Gas Price Spike Act HR 3784 said The term ‘reasonable profit’ means the amount determined by the Reasonable Profits Board to be a reasonable profit on the sale. It is then up to the board to subjectively determine what that profit is. (BTW this did not become law). [Addendum] It's actually very difficult to determine what reasoning judges use in those cases where they are the determiners of fact. They will likely call on their knowledge of law, asking "are these circumstances sufficiently like past circumstance A where the defendant was convicted, or more like B where the defendant was acquitted".
The most innocent of your scenarios is "against the rules", so less innocent acts fair worse. The idea behind researching legal theory and precedent (presumably not presidents) is that surely it is good for a juror to know what the law is. But that thinking is wrong. The judge will instruct you as to what the law is, and will also instruct you that "the law" is limited to what he says it is. I will draw on the instructions for an antitrust case, Best Buy v. Toshiba, HannStar. The core instruction is: It is your duty to find the facts from all the evidence in the case. To those facts you will apply the law as I give it to you. The preliminary instructions (the pattern instructions for California civil trials) say the same basic thing: At the end of the trial, I will explain the law that you must follow to reach your verdict. You must follow the law as I explain it to you, even if you do not agree with the law. The judge instructs the jury that: When a party has the burden of proof on any claim or affirmative defense by a preponderance of the evidence, it means you must be persuaded by the evidence that the claim or affirmative defense is more probably true than not true. Your research might find alternative statements of the law out there, which seem entirely plausible. That doesn't matter: you have to set aside whatever ideas (about the law) that you've gotten from anybody besides the judge. In fact, if the judge makes a (serious) mistake and rules against a party in a manner that is contrary to established law, and you know this (it doesn't matter how), you are supposed to apply the law (including rulings during trial as to admissibility) as given to you by the judge. As for a case of a juror knowing that the judge was mistaken (specifically, knowing based on his pre-existing knowledge of statutes and case law – not based on forbidden research during a trial), we can get the "should" from the absolute instruction to follow the judges instructions. Additionally, if you read transcripts of voir dire (not a trivial task), you can observe judges probing attorneys who happen to be in the prospective pool, asking questions to determine whether that person can just do as they are told. But it would be difficult to establish a "hard rule". There never will be an instruction that says "You must follow my orders even if you know for a fact that my orders are wrong" – jury instructions never admit the possibility of judicial error.