American Courts

"The judicial power shall extend to all cases, in law and equity, arising under this Constitution, the laws of the United States, and treaties made, or which shall be made, under their authority;--to all cases affecting ambassadors, other public ministers and consuls;--to all cases of admiralty and maritime jurisdiction;--to controversies to which the United States shall be a party;--to controversies between two or more states;--between a state and citizens of another state; --between citizens of different states;--between citizens of the same state claiming lands under grants of different states, and between a state, or the citizens thereof, and foreign states, citizens or subjects."

- 'U.S. Constitution, Article III, Section 2

First, you need to see American Federalism to get an idea that the power of the law is divided between the States and the Federal government.

Second, you should know that the states are allowed to set up different structures and procedures for their courts, and they do. Just about everything mentioned here about state courts will vary from state to state.

Third, you should know that as a former British colony, the United States uses The Common Law system at both the federal and state level (with the exception of Louisiana, which, being a former French colony, uses civil law except in criminal proceedings). This has a strong effect on how courts are set up and what they are and are not allowed to do.

Trial Courts
This is where the action (and the antics) takes place. Federal trial courts are known as "District Courts" and serve a judicial district consisting of all or part of a state. The names of these courts can get kind of weird; for instance, the federal District Court for the Central District of California is based in Los Angeles (the Southern District being in San Diego). State trial courts have different names depending on the state, but in fiction they'll invariably be called "Superior Courts" because that's what California calls them and the rest of the country is just like California, right? They usually serve one county each.

In addition to the U.S. Attorney General, there will be something equivalent to an Attorney General for each state, and in most states it is effectively a managerial post, in that most prosecutions have to be done by local District Attorneys, while the Attorney General executes and hammers out the details of the prosecutorial system. California and New York are the exceptions, the local District Attorney as well as the State Attorney General have the power to prosecute crimes. Furthermore, Delaware is rather unusual: because of the state's small size and population, the State Attorney General is responsible for criminal prosecutions statewide.

In the typical criminal trial, the following people will be present

 * The Judge - The United States, like most English-speaking countries, uses the "adversarial" system of trials, rather than the "inquisitorial" system used in most non-English-speaking countries. What this means is that the judge doesn't call witnesses and usually does not question them (but does have the power to do so) or present any evidence; those are entirely in the hands of the prosecutors and the defense attorneys. The judge's main duty is to resolve any issues of law that come up, usually when one attorney objects to the other's questioning as inappropriate, and to resolve questions on the admissibility of evidence before trial. The judge also instructs the jury (if the case is being heard by a jury) as to the relevant legal issues, i.e., whether or not certain actions would constitute a crime, and sets the sentence if the defendant is convicted.
 * Prosecutors - In federal court, known as U.S. Attorneys; in state court, known as District Attorneys (okay, not in every state, but both California and New York call them DAs, that's practically the whole country). In both cases the people actually prosecuting the case will have the title of "Assistant U.S. Attorney" or "Assistant/Deputy District Attorney", respectively, since the U.S. Attorney (appointed by the President) and the District Attorney (usually elected) are the heads of the prosecution offices for their respective districts/counties and rarely prosecute cases themselves. The prosecutor is either a tireless pursuer of justice or a callous Inspector Javert figure, depending, of course, on whether you think the defendant is guilty.
 * Defense Attorneys - Either a heroic Perry Mason type or an Amoral Attorney, again depending on whether you think the defendant is guilty. If the defendant can't afford an attorney, he or she is entitled to one, paid for by the government (that's the Sixth Amendment, applied against the states by 1963's Gideon v. Wainwright). There are two main ways of going about this:
 * Public Defender's Office: aka the "staff attorney model. Public Defenders are stereotypically overworked and woefully underfunded. The PDO will provide a Public Defender unless there's a conflict of interest, e.g. if there are two defendants and both are accusing the other of committing the crime, the public defender can't represent both and one of them gets a private attorney.
 * Judicare: Some jurisdictions forgo having an actual public defender's office and contract with private defense attorneys to represent indigent defendants. The name comes by analogy with "Medicare", and is broadly similar to the British system of Legal Aid (the main difference is that since the legal profession in the US is fused, the government doesn't have to pay both a barrister and a solicitor).
 * The defendant can also choose to forgo the attorney and represent him/herself; this usually makes the defendant look like a nutcase (the saying in the legal trade that someone who represents him/herself "has A Fool for a Client"), but hey, it was his/her choice. However, in high profile felonies where the defendant wants to represent themselves, the defendant will still receive an attorney so that the appeals court doesn't decide that they were denied adequate representation and overturn a conviction.
 * The Defendant - The person who, allegedly, dun it, though the defendant is considered to be "innocent until proven guilty." Will usually be found sitting at the table next to the defense attorney, looking morose.
 * Witnesses - Most of the trial consists of the prosecutors or defendants calling and questioning witnesses on the facts of the case. Witnesses can roughly be divided into eyewitnesses, who actually saw what happened, character witnesses, who know the defendant and can vouch for his/her good character (or against it, if called by the prosecution as rebuttal witnesses; legally the prosecutor cannot call character witnesses to impugn the defendant's character unless the defendant calls them to bolster his/her own character first), and expert witnesses, who don't actually have anything to do with the specifics of the case but explain medical/scientific/technical/otherwise obscure information that's relevant to what happened.
 * Bailiffs - The ones in usually (depending on the jurisdiction) in uniform. Their jobs may include (depending on the jurisdiction) announcing cases on the docket, escorting prisoners to/from the courtroom, and generally maintaining order. In federal court, they're in the U.S. Marshals Service; in state court, usually in the county sheriff's department.
 * Clerk(s) - In charge of keeping the paperwork in order (and there's a lot of paperwork). Most visible role in the courtroom is swearing in witnesses, though sometimes a bailiff or the judge will do this instead.
 * Stenographer - Sits next to the judge's bench typing up a transcript of the proceedings. Occasionally asked to read it back.
 * Court Artist - Many judges refuse to allow television cameras into the courtroom out of the belief that they would turn the trial into a media circus. (Judging from the O.J. Simpson trial, they're right.) So instead, in high-profile cases garnering media attention, an artist will sit in the gallery and draw or paint renditions of the scene for use in news coverage.
 * The Jury - Finally, the twelve randomly chosen schmoes who actually decide the case. Before the trial starts, both sides get to go through the jury pool and kick out any jurors they feel would be biased against them. The judge also kicks out anyone who does not meet their standards of impartiality (or cultural conformity). During the trial itself, the jury sits in its box at the side of the courtroom (and it's always the side that is closer to the prosecution, since it's the state that builds courthouses, the jury is always on the prosecutor's side) carefully observing the proceedings in order to come to the most just and impartial verdict...pfft, I can't say that with a straight face either, but usually most of them at least try to take things seriously. Most people consider jury duty somewhere around the sixth circle of Dante's Inferno, and try to find ways to get out of it as quickly as possible. (In rare cases, the defendant may request a "bench trial" in which there is no jury and the judge decides the verdict. Interestingly enough, the right to trial by jury is a right of the defendant only, if they decide to waive trial by jury, the prosecutor can't object and has to accept a waiver of jury trial.)
 * Note that in some types of criminal (or non-criminal trials, such as minor traffic offenses) which are called an "infraction", you can only be fined, you cannot go to jail, and in most states you cannot get a jury trial, you can only get a bench trial. Some states will, however, allow you a second trial and if you want to ask for it, you can get a jury trial then.
 * a "misdemeanor" is a class of crime which has a maximum penalty of a year in jail. However, if you're charged with a misdemeanor having six months in jail or less, in some states they can also force you to take a bench trial. As with infractions, some states allow an appeal and a new trial, and you may be able to get a jury if you want one. However, the U.S. Supreme Court has made it clear that you must have the option for a jury trial if you face more than six months in jail.
 * Technically, you can't get a jury trial in Chancery (see below), though in most jurisdictions this doesn't matter. There are also circumstances when you 'want' a bench trial. (Your suit is based on complex issues and arcane points of law that will bore the pants off of a juror).
 * The Audience. The Sixth Amendment to the Constitution of the United States guarantees to all criminal defendants a right to a public trial, which means that all criminal cases - in the absence of the prosecutor and/or the defendant asking for a closed trial—have to be open to the public for anyone who wants to walk in to watch. This is not just because it can be entertaining for the public—although that's often a nice benefit - but it's to protect the defendant against a Hanging Judge and Amoral Attorney holding Kangaroo Court in secret.

Events in a criminal case

 * Arraignment - in which the defendant is released from police custody or brought in from jail, is read the charges, and pleads guilty or not guilty. The judge sentences the defendant (if they plead guilty) or sets bail, accordingly.
 * Grand Jury Indictment - in federal cases and some states, the prosecutor can't bring charges without an indictment from a grand jury. The grand jury consists of traditionally 23, but today often fewer, randomly chosen citizens, and at least 12 of them must agree that there is sufficient evidence to prosecute for the DA to get the indictment. Since the grand jury only sees the prosecution's evidence, this has led to a joke among attorneys that a Grand Jury would indict a ham sandwich, but, yes, there are rare instances where a Prosecutor's evidence is just that weak a Grand Jury doesn't bring the indictment. Though the Prosecutor is free to try again with another Grand Jury, many will not and that lets it go. Many states do not require a grand jury for most or any proceedings, though they often still maintain them as an investigative tool or for the prosecutor to get a chance to pre-try a case that might be weak or questionable.
 * The point is mostly to keep the prosecutors in line—if all their evidence, presented entirely unquestioned and without any alternate theories, is not enough to get 12 people to say "yeah, that guy probably did it", they shouldn't be wasting the court's time with a case that will surely result in an acquittal. The Grand Jury is there to make sure they can't.
 * The terminology and order is completely inconsistent between federal and state cases and between states on whether the "arraignment" is the hearing before or after the indictment, or whether the indictment is needed at all. Fortunately, this is irrelevant unless you've been arrested or you're a lawyer, in which case you're fracked anyway.
 * Grand Juries have their own subpoena and investigatory power independent of the Prosecutor who is presenting to them. It is extremely rare, but can happen, that a "Runaway" Grand Jury can actually eject the Prosecutor from the room and run their own investigation, taking it wherever the evidence leads. Additionally, the Grand Jury testimony is secret. Not even the defendant is allowed into the room (unless he or she is called as a witness). The only ones who can legally reveal what was said are the witness that said it and, in very limited circumstances (like that witness being murdered) the Prosecutor. Also, testimony in the Grand Jury room is under oath, so lying is serious, not an Empty Cop Threat.
 * Motions, Hearings, etc. - in which both sides' attorneys build their cases and file motions with the judge to include/exclude certain evidence or force the other side to give information up. Takes a few months up to a year, of which only a few days will be spent in court. Most cases criminal or civil, are won or lost at this stage. Unlike TV, the vast, vast majority of criminal cases end with a plea bargain or dismissal. If criminal charges were brought without a grand jury indictment, then the first hearing will typically be a preliminary hearing, in which the judge rules on whether there is probable cause to hold the defendant over for trial.
 * Trial - the interesting part. First the prosecution and defense make statements to the jury outlining their theories of the case. (Once the jury is sworn in, that's when "double jeopardy attaches." Barring extraordinary circumstances, the prosecution has to see it through to the end, or they can never charge that person again for the same crimes.) Then the prosecution calls and questions witnesses, each of whom the defense may cross-examine. Then, vice versa: the defense questions their witnesses and the prosecution cross-examines. Then, closing statements, and the jury is sent out to deliberate. The whole thing rarely takes more than a week, though there are exceptions (see, again, the O.J. Simpson trial).
 * Jury Deliberations - in which the jury argues among themselves over whether the defendant did it. In many jurisdictions, and in federal court, a verdict must be unanimous, or else it's a mistrial and we start again with a new jury, so if there's disagreement things can get pretty heated.
 * Sentencing - if the verdict is guilty, this is when the judge sets the sentence. There has to be a separate jury determination for the death penalty.

And in civil lawsuits...
If it's a civil lawsuit rather than a criminal trial, replace the prosecutor with the plaintiff's Ambulance Chaser attorney. The rough sequence for a civil case is:


 * Pleadings - in which the plaintiff accuses the defendant of wronging him/her in a complaint. This must be served upon the defendant, and a whole cottage industry of "process servers" exists to make sure the defendant physically receives the papers. Usually today, the defendant is mailed the complaint and the process server is only brought in if the defendant doesn't respond to the mailing. The defendant typically responds by an answer to the complaint, which very often will include their own complaints against the plaintiff(s) and possibly also against third-parties at the same time (which they are required to bring in the same case or else risk losing the opportunity to ever plead them under a doctrine known as "res judicata" or "claim preclusion"). Alternatively, the defendant can make any of several motions or pleadings, depending on the procedural rules of the jurisdiction, that seek to have the complaint dismissed or parts of it stricken on procedural grounds. Examples would include claiming lack of jurisdiction by the court, insufficient service of process, or on the grounds of legal insufficiency, in which the defendant claims that even if everything in the complaint were true, the plaintiff hasn't made out a claim entitling them to any legal relief. If there is a clear legal result based on what is undisputed on the face of the parties' pleadings, either of the parties may make a motion for the court to enter a judgment on the basis of the pleadings alone.
 * Discovery - Once the defendant has responded to the complaint, the long process of discovery begins. The parties have the right to demand vast quantities of information from each other to figure out the precise facts of the case for trial. There are motions and hearings throughout this phase as well to bring new claims, counterclaims, cross-claims, as well as to compel evidence and dismiss certain claims. This can all get very complicated very fast, can drag on for years, and is almost always the most expensive and time-consuming phase of civil litigation. Discovery in complex civil litigation often turns into a major contest in and of itself, as each side may try to strategically wear down the other's resources by forcing them to comply with burdensome discovery requests while seeking legal means to avoid having to produce material themselves, such as by claiming that it is outside the defined proper scope of discovery or is somehow protected or privileged. Courts do retain powers though to sanction (punish) parties and their attorneys who fail to comply with discovery or who otherwise abuse the process too flagrantly (by ordering them to pay money to the other party, deeming certain relevant issues admitted, or even dismissing a party's case outright in severe cases). Most cases will be resolved by the end of discovery, either by a settlement between the parties or by "summary judgment" by the court based on undisputed material facts produced in discovery.
 * Trial - If the parties haven't settled and the case hasn't been dismissed or disposed of through summary judgment, it goes to trial. Trials are intended to resolve remaining disputes of fact between the parties, rather than law or factual issues that have already been agreed upon or decided. The factual disputes they are intended to resolve may often be limited by summary judgment or stipulation by the parties, such as on the amount damages even when one party has admitted liability. The United States is almost unique in using the jury in civil cases, though often with six jurors instead of twelve, depending on the jurisdiction. Some states allow a non-unanimous verdict of varying majority. Civil trials are exceedingly rare (less than 5% of all cases end up here) and usually the end of the matter, provided there's no appeal.

One more thing about criminal vs. civil trials: The prosecution in a criminal trial must prove to the jury "beyond a reasonable doubt" that the defendant is guilty. This means if the jurors are not completely convinced that there is no other realistic possibility than "the defendant did it," then they are supposed to find him/her not guilty. On the other hand, civil trials are based on "the preponderance of the evidence," which means that the jury only has to find one side's argument more likely than the other's.

Appeals
If one party thinks the case has gone the wrong way, he/she can appeal the verdict to a higher court. This can only happen for matters of law, not of fact, unless the trier of fact has made a clear error in the findings of fact: "The evidence against me was improperly allowed" is a valid appeal, "I didn't do it" is not.

There is an exception for criminal cases in state court where the defendant was convicted and sentenced to death, by law a mandatory appeal is automatically filed to the State Supreme Court (or whatever the highest criminal court in that state is) which must approve the conviction for the sentence to be valid and carried out. The defendant cannot waive this appeal even if they wanted to be sentenced by the trial court and wanted to die quickly. Of course, if the defendant doesn't file any papers then the appellate court would only have the prosecution's side, so the conviction would be upheld anyway...

An appellate court will typically have three judges presiding. Federal appeals go to the "Court of Appeals for the Nth Circuit", where N is a number from 1 to 11 (or Washington D.C., which has its own). The circuits are laid out geographically. Here's a handy map. The federal court system also has a separate circuit, the Federal Circuit, defined by subject matter rather than geography; it is best known as the court of appeals for patents and government contracts. Most states are similar. Circuit Courts are often saddled with the reputation of the city where they sit. The Ninth Circuit (San Francisco) is often criticized for being too liberal, the Second Circuit (New York City) being too pro-business, and the Fifth Circuit (New Orleans) being too harsh on criminal defendants, for example.

Note that an appeal must only be on a single issue, and appellate courts can't look at any new evidence, but must rely on the trial court's record. There will be no witnesses and no jury, simply the two attorneys arguing their cases before the judges. The appellate court's decision may affirm the trial court's decision, or may overturn the decision and order the proceedings to continue or a new trial to be granted depending on the specifics of the case. On certain procedural matters and rulings in trial court before a final judgment, an appellate court may review the lower court's decisions by means of an "interlocutory appeal" and either affirm the lower court's ruling or reverse it.

Depending on the type of case, there may be more than one court that can be appealed to. For example, in some states there is an intermediate court of appeals, where certain cases are final, and in rare instances those cases can be appealed to the state's highest court, which is usually called the Supreme Court (of the State of X), so as not to confuse it with the absolute, final appeals court for all cases tried anywhere in the U.S., which is where we get to...

United States Supreme Court
Should the loser of the appeal want to appeal again, and if he or she is appealing from federal court or from state court of last resort on the basis of issues of federal law, he/she must submit a petition to the Supreme Court. The United States Supreme Court is the "court of last resort", and their decisions are final. As the highest court in the land, the Supreme Court's time is very precious, and they will only accept a petition if the case is of national importance. Of the thousands of petitions they receive, less than 200 are typically accepted. The estimate is about 1% of all "petitions for writs of certiorari" (fancy talk meaning a notice filed with a lower court that the case is being appealed to the U.S. Supreme Court) is accepted by the court. If they don't accept the case, then the existing ruling stands, and that's final. The US Supreme Court (and many state supreme courts) practice "discretionary review," meaning that they decide whether or not they wish to review a particular case, as opposed to "mandatory review" by lower courts that must accept appeals.

In theory, the less then 200 cases they agree to accept are the ones where there is "national importance" regardless of the person petitioning. However, if you happen to pay attention, you would notice that rich and/or influential people seem to get their appeals heard far more often then would be expected.

Also the terms for those involved are different. The party who files an appeal (the first name on the lawsuit) is still the "plaintiff" and the other party is the "defendant". In most appeals courts, the appealing party is the "appellant" and the responding party is the "apellee." In the U.S. Supreme Court, the one who files an appeal is the Petitioner, and the other party is the Respondent, e.g. in Roe v. Wade, Jane Roe (later revealed to be a woman named Norma McCorvey) was the Petitioner, while Henry Wade (the District Attorney of Dallas County, Texas) was the Respondent. The majority of the Supreme Court's work is in handling cases within its appellate jurisdiction, though it has original jurisdiction (meaning that it can be the first court to hear a particular case) in matters involving ambassadors and diplomats, or when one state is suing another. (To this day, a surprising number of cases in the Supreme Court—typically about 1-3 a year—are states suing each other, primarily because states do get into legal disputes with some regularity, and the "original jurisdiction" thing means that there's literally nowhere else they can sue one another—the Supreme Court can't turn them down. One imagines that the justices get rather annoyed and look upon all potential interstate disputes with some trepidation.)

Usually the Supreme Court decides whether a certain law or governmental practice violates the Constitution. If so, the law or practice is struck down as unconstitutional and all lower courts must follow this ruling in the future. Lower courts may also strike down a law as unconstitutional, but their rulings are only binding precedents within their own territorial jurisdictions. Indeed, the Supreme Court will frequently hear cases that are "circuit splits", where the US Courts of Appeals have come to different conclusions on the same issue.

Supreme Court decisions are a Big Deal, and massive outcries result whenever they do anything the least bit controversial. Whenever anyone refers to "activist judges", read "judges who made decisions I disagree with". This tends to come from both sides of the aisle, and the definition is recognised by both sides as well; at least one former Republican Solicitor General has agreed with said definition.

Membership
The court's membership does not have its number set by The Constitution, but is currently nine. In alphabetical order, they are: Samuel A. Alito, Stephen G. Breyer, Ruth Bader Ginsburg, Elena Kagan, Anthony Kennedy, Chief Justice John G. Roberts, Antonin Scalia, Sonia Sotomayor, and Clarence Thomas.

The last attempt to change it was by Franklin D. Roosevelt, and it didn't go down well. Members are nominated by the President and confirmed by the Senate. The Senate does hearings and its confirmation is not always forthcoming—Reagan nominee Robert Bork wasn't confirmed, and recent nominee Harriet Myers withdrew her nomination when it became clear she wouldn't be either—but, since the usual practice is to have Congress informally vet a prospective nominee before officially nominating him/her, confirmation usually follows swiftly. Members stay in post until they retire, die or are impeached for misconduct. Justices are addressed as "Justice so-and-so", even outside the court, a weakened version of a tradition inherited from the British system. More stylistically-conservative legal scholars will generally use the full British terms of reference in writing; do not be surprised to see a constitutional law book speaking of "Mr. Justice Scalia," "Mr. Chief Justice Roberts," and "Madam Justice Sotomayor."

The Chief Justice is the guy in charge and assigns the writing of the majority opinion (if he is on the side of the majority; if not, the longest serving justice on the side of the majority assigns the writing of the majority opinion), and can assign it to themselves if they want. The current Chief Justice is John Roberts (2005-), meaning we are in the Roberts Court. It is split between liberals and conservatives, going 5-4 a fair bit these days. The previous Chief Justice was the late William Rehnquist, who spent 19 years in the post and quite a while as an Associate Justice before that. Rehnquist spent the last 10 years of his CJ period with four gold stripes on his robe, because he saw a production of Iolanthe and thought the Lord Chancellor's robes looked cool. Roberts did not continue the practice and everybody else wears plain black robes, although the women justices will from time to time wear a white collar (a tradition started by the first woman justice, Sandra Day O'Connor) along with the robes.

The Chief Justice also has additional responsibilities. He is also the administrator of the Federal Court system, which in effect means the Chief Justice has the equivalent responsibility of a Presidential Cabinet Department such as the State Department or the Department of Agriculture. The Chief Justice also selects the judges to be assigned to the super-secret FISA court which issues special warrants in cases where suspected Intelligence issues or sensitive National Security issues are involved. Traditionally the Chief Justice swears in the President, although any person who has the authority to swear someone to an oath may do so. In theory that means the President could be sworn in by a notary public, but the only time it ever had to be done other than by the Chief Justice, a judge is the one who is allowed to do so, as happened when Lyndon Baines Johnson famously took the oath of office while on a plane trip back from Dallas (administered by a local federal judge) after President John Fitzgerald Kennedy was assassinated. Finally, the Chief Justice presides at any trial by the Senate of the President, which has happened only twice in US history, both times ending in acquittal. The first was of Andrew Johnson in 1868, the next Bill Clinton 130 years later.

It is not necessary to be an Associate Justice before being Chief Justice (Roberts was appointed Chief Justice without ever having served as an Associate Justice), or even a judge (Kagan had never been a judge before being appointed to the High Court). Or, technically, even a lawyer, although the President is not going to appoint someone who isn't a lawyer to the court unless he wants the nomination to fail, because the American Bar Association is going to come back and declare the nominee unqualified.

Fun fact: Since the 2010 retirement of John Paul Stevens, there are no Protestants on the Court. Justices Ginsburg, Breyer, and Kagan are Jewish; the remaining six Justices are Catholic.

Opinions
The Supreme Court will issue up to three types of ruling per case. Not every Justice has to write one; most will sign one that someone else has written. Justices can also be selective, agreeing with another except for Part X or Footnote Y. Supreme Court rulings are occasionally good source of witty quotes (Justice Potter Stewart's "I know it when I see it" on pornography for example).

The types are:
 * The majority opinion. The one that counts. The justice with the most seniority on the side with the most justices agreeing with the decision gets to decide who writes the opinion. This means the Chief Justice if they agree with that side, else the justice with the highest seniority. (In some cases the Chief Justice has sometimes changed sides and voted in opposition to their own feelings on the case, just so they could write the majority opinion. This is more than ego at work—the Chief Justice who does this can then write the opinion in a manner more consistent with their judicial philosophy, potentially limiting the impact of the case.)
 * Concurring opinion. Agreeing with the ruling, but on different grounds. May be more than one. In some instances, the Concurring opinion will be held in higher regard than the Majority opinion, but this is rare (The most famous occurrence of this being Justice Jackson's opinion from Youngstown Sheet & Tube v. Sawyer).
 * Dissenting opinion. Exactly how it sounds. No legal force. May be up to four. However, should the Court decide to reverse a previous decision, it might rely on a dissent for guidance and justification (essentially saying "the majority didn't know what it was doing, but this other justice knew what was up"). The most important example is probably the 1941 case United States v. Darby, where the Supreme Court reversed its decision in 1918's Hammer v. Dagenhart, explicitly citing Justice Oliver Wendell Holmes' dissent in that case as justification.
 * Concur/Dissent. While a Justice often signs on to the opinion of another Justice, a Justice is not required to sign on to all of another Justice's opinion. Sometimes, a concurrence or a dissent will omit a portion of that other Justice's opinion.
 * One of the more notable is with respect to the plurality decision (for which see below) in 1992's Planned Parenthood v. Casey, where the plurality opinion by Justice O'Connor was so weird and complicated that all of the other opinions both concurred with and dissented from it: since it upheld Roe v. Wade but upheld certain provisions of the Pennsylvania statute that would be struck down under a "pure" reading of Roe, it meant that both Justice Blackmun's opinion (following Roe—which he had written—to the letter) and Justice Scalia's opinion (which would have struck down Roe altogether) were considered to both concur and dissent in the Court's decision.
 * The only way to figure out what parts of the opinion got a majority (and thus became precedent) and which didn't is to literally draw up a chart: you see, O'Connor was joined by Kennedy and Souter; Stevens and Blackmun both wrote their own opinions more liberal than the O'Connor one but in different ways and on different grounds; and Rehnquist, Scalia, Thomas, and White all joined two opinions—penned by Rehnquist and Scalia—that were more conservative than the plurality, but in different ways and on different grounds. In other words, teaching this case is a nightmarish day of utter confusion for even the most adept student.
 * One of the more infamous is Flood v. Kuhn, where Justice Blackmun (again) used a section of a Supreme Court decision to write an off-topic essay about how cool baseball was. No one who signed on with his decision signed on with that section.

There is possibility of a plurality rather than a majority. If no majority of Justices agree, whoever has the most wins, but the decision isn't the final in the same way.

Oh and it can, and does and for the next year will be splitting. Justice's must recuse if they have an affected interest. For example, the case allowing Women to be admitted into the Citadel had no vote by Thomas because of his son's attendance at the school. The court is split 5-4 on many issues due to ideology. However, newly appointed Justice Kagan was Solicitor-General, the lawyer whose job it is to present cases to the Supreme Court. Approximately half the cases until June will only have 8 justices voting because Kagan recused herself due to working on the presentation of the cases. Omega v. Costco where Omega Watches sued Costco for buying watches overseas and importing them for lower than Omega's American prices, is the first of a 4-4 split, which means the lower court decision stands as precedent. In Omega that means an American Rights hold who sells a good overseas didn't really sell it until he sells it in the US.

Note that the "must recuse" is a misnomer. Only the Justice them self decides if they have a conflict of interest or not. If the court was deciding if the Justice's son would be executed or not, the Justice still wouldn't have to recuse themselves. (Although it is likely in that case they would be impeached rather quickly).

The court can—and has—reversed itself, most famously in 1954's Brown vs. Board of Education, where it unanimously reversed Plessy v. Ferguson, an 1896 decision that upheld segregation if it was "separate but equal". By 1954, they agreed that it was wrong. Thurgood Marshall, the NAACP lawyer in this case, would become the first black Justice. Likewise, sodomy laws were upheld in 1986's Bowers v. Hardwick but overturned in 2003's Lawrence v. Texas.

Another famous instance where the Court has reversed itself is in 1941, when the aforementioned United States v. Darby overturned Hammer v. Dagenhart, allowing the federal government to pass whatever restrictions on interstate commerce it pleased for the purposes of social legislation. Sometimes a case is clearly overturned, but precisely where is uncertain; for instance, it is widely agreed that Lochner v. New York (which struck down a New York law that kept bakers from working more than ten hours a day or 60 hours a week—yes, we know what you're thinking) was (mostly) overturned, but which case exactly did the overturning is the subject of lengthy debate by legal scholars.

State Supreme Courts
State supreme courts are similar, but on a smaller scale, and decide on issues of state law. Though the federal Supreme Court has found that the death penalty is not "cruel and unusual punishment" under the federal Constitution, several states have banned it as "cruel and unusual" under state constitutions or state law. In some states, their State Constitution will prohibit punishments which are cruel or unusual, not merely both. If the state supreme court is deciding on a matter of both state and federal law, then appeals are possible to the federal Supreme Court; if it's pure state law (like the gay marriage decisions in Massachusetts and, California, Iowa and Connecticut), no further appeal is possible.

In a few small states, there's no intermediate Court of Appeals, and all appeals go directly to State Supreme Court. Also, the name of the court may vary from state to state - a notable example is New York, where the Supreme Court is actually NOT the supreme court of New York (that would be the Court of Appeals). Maryland's highest court is called the Court of Appeals, and it's the only court in the U.S. where the judges do not wear black robes. In most states, the head judge and the other judges of the highest court are called the Chief Justice and associate Justices. Again, except Maryland, again, where the Chief Judge and Associate Judge of the Maryland Court of Appeals wear red robes. Probably a holdover from Britain where some of the judges' robes are red as well.

Note that State Supreme Court justices do have to recuse themselves if there is a conflict of interest. In a very nasty case, Caperton v. A.T. Massey Coal Company, Justice Benjamin of the West Virginia Supreme Court had received more than 1/2 of the funds needed to run for election to the Supreme Court seat from a group sponsored by Don L. Blankenship, the president of Massey Coal. He refused to recuse himself, and ruled in favor of Massey. The U.S. Supreme Court took a dim view of this and reversed the decision.

Miscellany
A few states have notable oddities in their judicial systems:
 * New York has a perversely complicated court system, made even more so by the weird naming. The New York Supreme Court is a trial court, akin to the Superior Court in California; the intermediate appeals court is the Appellate Division of the Supreme Court; and the high court of the state is the Court of Appeals. (This isn't even getting into the half-dozen other courts in the state.)
 * Massachusetts also enjoys weird naming to a lesser extent: the highest court in the Commonwealth is the Supreme Judicial Court. This sounds redundant, but it is actually to distinguish it from the legislature, which is called the General Court (and which used to be a court too, but not anymore).
 * Bizarrely, Maine also has a "Supreme Judicial Court" despite the fact that the name of its legislature has always just been "the Maine Legislature"; and infuriatingly, New Hampshire's highest court is the "New Hampshire Supreme Court" despite the fact that the New Hampshire legislature is also called the General Court.
 * The states of Texas and Oklahoma are the only states in the Union to have a bifurcated court system, with two separate branches for civil and criminal cases.
 * In Texas, this works out to having two high courts and several different county level courts. At the municipal level, you have the Justice Courts for small claims, while the Municipal Courts involve criminal cases punishable by fine only and ordinance cases. At the county level you have the Constitutional County Court which handles all county level cases, with County Court-at-Laws having limited authority in order to help ease the workload in counties with large population densities. The District Courts have authority over civil actions under $5,000, divorce, title to land, felonies, juvenile matters, etc. Appeals from the county-level courts and district level courts are heard in the Courts of Appeals (14 such courts exists in Texas). If the case cannot be resolved or the appeal is approved, it goes to one of the high courts. If it's a civil case, it goes on the Supreme Court of Texas. If it's a criminal case, it goes to the Court of Criminal Appeals.
 * Furthermore, in Texas all judges are elected rather then appointed. (This makes sense when you consider the state's culture heavily favors Jacksonian style politics.) Also unlike most states in which judges are elected, they are elected on an explicitly partisan ticket (in most states with judicial elections, judges are nominally non-partisan, although in practice judges' political leanings are public knowledge). This includes justices for the Supreme Court and the Court of Criminal Appeals. There is also no requirement for running for Justice of the Peace, save that afterwards you're willing to take the equivalent of three college courses.
 * Delaware, by chance, had a very corporation-favoring court. Because of some corporate quirks like the way they're treated a citizen of where they incorporate, corporations decided that Delaware was the go-to locale. This leads to most "big" corporations wanting to incorporate in Delaware, regardless of where in the U.S. they are. Over time, the Delaware court has become less pro-corporation (maybe), but here's the thing: because Delaware was a center for corporate lawsuits for so long its corporate law is the most developed in the U.S., to the point that other states look to what Delaware does for guidance. It even has a separate court for corporate issues. And people still want to incorporate there, not because its courts favor corporations, but because virtually every corporate issue has been tried there, so there's no unpredictability.
 * Louisiana has a Civil Law system modeled on the Napoleonic Code, rather than the English Common Law system practiced everywhere else. Again, the distinction is largely insigificant unless you are a defendant or lawyer, although it does mean that Loophole Abuse is easier in Louisiana courts than elsewhere: one of the features of the common law is that the judge has extensive power to declare "no loopholes", especially in civil cases; the French law, developed out of a visceral hatred of judge-made law (see The Other Wiki's article on the ancien regime parlements for why), has no such provision.
 * Virginia has District Courts that handle small claims, misdemeanors and traffic offenses. Cases involving $15,000 or more, felonies and death penalty cases are tried exclusively in Circuit Court. If you lose in District Court you also have the right in any case to appeal for a new trial, or Trial de Novo at Circuit Court. In a Virginia Circuit Court you always have the right to a trial by jury in every single case. Virginia is one of only two states (Vermont being the other one) where, if you're willing to pay for the cost if you lose, that you could actually get a jury trial on a parking ticket.

There are some subject-matter-specific trial courts in many states. The precise names and jurisdictions of these courts differ from state to state, yadda yadda yadda.
 * Family Court: Can handle issues involving adoption, divorce, juvenile offenders, inheritances, etc.
 * Probate Court: Settling wills and issues of who gets what when someone dies.
 * Traffic Court: Many states have special proceedings to challenge traffic tickets. Instead of wasting lots of people's time with a full jury trial for a parking offense, in traffic court it's just the offender, the ticketing officer, and the magistrate (sometimes not even a full judge). In some states the officer doesn't even need to show up, so appeal a ticket and you're only wasting your own time.
 * Small Claims: To avoid the expense of the whole lawsuit rigmarole, there are special tribunals for cases under, say, $5000, in which no lawyers or juries are present and the judge questions the plaintiff and defendant on their stories, then makes a decision. There can be some good stories in Small Claims court, hence the "courtroom shows" (The People's Court, Judge Judy, etc.) that take the form of a Small Claims court with a retired judge presiding. (Technically these shows are private arbitration, not public courts of law, but nobody would watch a show called The People's Binding Arbitration Tribunal or Arbitrator Judy, now would they?) Hmm...
 * Landlord-Tenant: Exactly What It Says on the Tin.
 * Special Arbitration: Most binding contracts and all labor agreements include provisions for settling disputes in arbitration. This is similar to a bench trial, but does not involve witness testimony (only arguments and witness depositions) and is usually conducted in closed session. In addition, arbitrators are rarely actual judges, but rather highly experienced attorneys. This is all done to avoid cluttering up the courts, and to make sure the party who wrote the contract wins most of the time, because if the arbitrators found in favor of the other party too often the company writing the contract would switch to a different arbitration organization. Appeals (when allowed) filter into the civil court system.
 * Companies contracted by the federal government are not allowed to force arbitration for all issues, after a woman working in Iraq was gang-raped by contractors working over there and lost her arbitration trial (despite one of the rapists admitting to it).
 * Chancery aka Equity...is a long topic, so this is a quick & dirty version. The legal system is the result of the merger of two legal systems. Before the systems were joined, there were cases at law and cases at chancery/equity. You would wind up in different courts, depending on what the problem was. The distinction often seems strange and arbitrary. (For instance, someone squatting on your land? Law. But a tenant doesn't move after the lease? Chancery). In fact, because of its strangeness and arbitrariness, most jurisdictions sought to eliminate the distinction as much as possible. But not all jurisdictions did, and there's a lot of technical differences between the two (specifically in what you can get out of the lawsuit (money or actions tend to be the difference)), which may or may not be observed by the court.
 * A famous (to people who follow this sort of thing) example of this is 1950's United States v. Louisiana, which, since it consisted of the federal government suing a state, was under the Supreme Court's original jurisdiction; Louisiana moved to have a jury trial, which was denied by the Supreme Court on the grounds that it was an equity action rather than a law action. If the Court had let the motion go through, it would have been the first jury trial before the Supreme Court since 1794.

The death penalty
The United States is about the only democratic industrialized nation (with the exceptions of Japan and Taiwan) that still puts its citizens to death. While the majority of Americans support the idea of executing "murderers", some current scandals have reduced support. First, DNA evidence started to show that a number of people on death row (as well as others who were sentenced to life imprisonment) were actually innocent. Secondly, a large amount of support for the death penalty always revolved around the myth of "I'm paying a huge amount of taxes to provide murderers in prison cable TV and luxuries". Instead, states are starting to rethink it because the current budget crises make the huge cost of death penalty trials an expense they can't afford. Proponents will argue, however, that there is very little evidence that post-Furman states have actually executed an innocent man, and that the cost issue is due to opponents of capital punishment putting up legal roadblocks (in particular, the federal court system has allowed numerous habeas corpus appeals from the same inmates in contravention of a 1996 statute).

There are also the issues where the imposition of the death penalty is restricted. Rape of an adult - Coker v. Georgia, 433 U.S. 584 (1977); Child Rape - Kennedy v. Louisiana, 554 U.S. 407 (2008) (In fact Kennedy declared the death penalty cannot be imposed where the victim does not die, except in treason and terrorism cases); crimes committed by a person under 18 - Roper v. Simmons, 543 U.S. 551 (2005); and crimes committed by the mentally retarded - Atkins v. Virginia, 536 U.S. 304 (2002); are prohibited from being made death penalty eligible. So the only things left for which the death penalty can be applied is exclusively to crimes where the perpetrator is over 18 and of normal intelligence and where someone died as a result of the crime, or to crimes of treason and possibly those involving terrorism.

In addition the Supreme Court has very limited jurisdiction over U.S. military courts-martial, and the Uniform Code of Military Justice as currently written allows a general court-martial to sentence individuals to death for murder and rape, as well as certain offenses in wartime (desertion, mutiny, espionage, cowardice, etc.). Executing a service member for a strictly military offense has only been carried out once (in 1945) since the end of the Civil War, and no military executions have been performed at all since 1961, although there are individuals sentenced to death (all for murder). The President of the United States must personally assent to any and all executions carried out by the military.

Rarely mentioned is the fact that any murder case where the Prosecution announces they are seeking the death penalty means that any prospective jury member who opposes capital punishment is barred from serving on the jury. This just happens to remove a large number of people from getting to decide if someone is guilty or innocent, including those most likely to question the prosecution's case. The unfairness, or mere existence, of this is largely known in the general public...until they get called to such a case. This is, however, not limited to capital cases; a jury empaneled for any crime must be willing to consider the full range of court-provided punishments (drug legalization proponents can't sit on a jury for drug-related crimes, just to provide one example).