Polaris Misdemeanor Lawyer, Montana, page 11

An affirmative defense to a crime. Self-defense is the use of reasonable force to protect oneself from an aggressor. Self-defense shields a person from criminal liability for the harm inflicted on the aggressor. For example, a robbery victim who takes the robber's weapon and uses it against the robber during a struggle won't be liable for assault and battery since he can show that his action was reasonably necessary to protect himself from imminent harm.

Intentionally restraining another person without having the legal right to do so. It's not necessary that physical force be used; threats or a show of apparent authority are sufficient. False imprisonment is a misdemeanor and a tort (a civil wrong). If the perpetrator confines the victim for a substantial period of time (or moves him a significant distance) in order to commit a felony, the false imprisonment may become a kidnapping. People who are arrested and get the charges dropped, or are later acquitted, often think that they can sue the arresting officer for false imprisonment (also known as false arrest). These lawsuits rarely succeed: As long as the officer had probable cause to arrest the person, the officer will not be liable for a false arrest, even if it turns out later that the information the officer relied upon was incorrect.

One of the most sacred principles in the American criminal justice system, holding that a defendant is innocent until proven guilty. In other words, the prosecution must prove, beyond a reasonable doubt, each element of the crime charged.

A party's job of convincing the decisionmaker in a trial that the party's version of the facts is true. In a civil trial, it means that the plaintiff must convince the judge or jury 'by a preponderance of the evidence' that the plaintiff's version is true -- that is, over 50% of the believable evidence is in the plaintiff's favor. In a criminal case, because a person's liberty is at stake, the government has a harder job, and must convince the judge or jury beyond a reasonable doubt that the defendant is guilty.

A prosecution for murder in which the jury is also asked to decide if the defendant is guilty and, if he is, whether he should be put to death. When a prosecutor brings a capital case (also called a death penalty case), she must charge one or more 'special circumstances' that the jury must find to be true in order to sentence the defendant to death. Each state (and the federal government) has its own list of special circumstances, but common ones include multiple murders, use of a bomb or a finding that the murder was especially heinous, atrocious or cruel.

Latin for 'You have the body.' A prisoner files a petition for writ of habeas corpus in order to challenge the authority of the prison or jail warden to continue to hold him. If the judge orders a hearing after reading the writ, the prisoner gets to argue that his confinement is illegal. These writs are frequently filed by convicted prisoners who challenge their conviction on the grounds that the trial attorney failed to prepare the defense and was incompetent. Prisoners sentenced to death also file habeas petitions challenging the constitutionality of the state death penalty law. Habeas writs are different from and do not replace appeals, which are arguments for reversal of a conviction based on claims that the judge conducted the trial improperly. Often, convicted prisoners file both.

A trial that ends prematurely and without a judgment, due either to a mistake that jeopardizes a party's right to a fair trial or to a jury that can't agree on a verdict (a hung jury) If a judge declares a mistrial in a civil case, he or she will direct that the case be set for a new trial at a future date. Mistrials in criminal cases can result in a retrial, a plea bargain or a dismissal of the charges.

A crime consisting of physical contact that is intended to harm someone. Unintentional harmful contact is not battery, no mater how careless the behavior or how severe the injury. A fist fight is a common battery; being hit by a wild pitch in a baseball game is not.