Chichester Juvenile Law Lawyer, New York

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.

A mental defect or disease that makes it impossible for a person to understand the wrongfulness of his acts or, even if he understands them, to ditinguish right from wrong. Defendants who are criminally insane cannot be convicted of a crime, since criminal conduct involves the conscious intent to do wrong -- a choice that the criminally insane cannot meaningfully make. See also irresistible impulse; McNaghten Rule.

The money paid to the court, usually at arraignment or shortly thereafter, to ensure that an arrested person who is released from jail will show up at all required court appearances. The amount of bail is determined by the local bail schedule, which is based on the seriousness of the offense. The judge can increase the bail if the prosecutor convinces him that the defendant is likely to flee (for example, if he has failed to show up in court in the past), or he can decrease it if the defense attorney shows that the defendant is unlikely to run (for example, he has strong ties to the community by way of a steady job and a family).

A negotiation between the defense and prosecution (and sometimes the judge) that settles a criminal case. The defendant typically pleads guilty to a lesser crime (or fewer charges) than originally charged, in exchange for a guaranteed sentence that is shorter than what the defendant could face if convicted at trial. The prosecution gets the certainty of a conviction and a known sentence; the defendant avoids the risk of a higher sentence; and the judge gets to move on to other cases.

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 term that describes vigorous questioning, usually by the police of a suspect in custody. Other than providing his name and address, the suspect is not obligated to answer the questions, and the fact that he has remained silent generally cannot be used by the prosecution to help prove that he is guilty of a crime. If the suspect has asked for a lawyer, the police must cease questioning. If they do not, they cannot use the answers against the suspect at trial.

A formal investigation -- governed by court rules -- that is conducted before trial. Discovery allows one party to question other parties, and sometimes witnesses. It also allows one party to force the others to produce requested documents or other physical evidence. The most common types of discovery are interrogatories, consisting of written questions the other party must answer under penalty of perjury, and depositions, which involve an in-person session at which one party to a lawsuit has the opportunity to ask oral questions of the other party or her witnesses under oath while a written transcript is made by a court reporter. Other types of pretrial discovery consist of written requests to produce documents and requests for admissions, by which one party asks the other to admit or deny key facts in the case. One major purpose of discovery is to assess the strength or weakness of an opponent's case, with the idea of opening settlement talks. Another is to gather information to use at trial. Discovery is also present in criminal cases, in which by law the prosecutor must turn over to the defense any witness statements and any evidence that might tend to exonerate the defendant. Depending on the rules of the court, the defendant may also be obliged to share evidence with the prosecutor.

The privilege that allows the president and other high officials of the executive branch to keep certain communications private if disclosing those communications would disrupt the functions or decisionmaking processes of the executive branch. As demonstrated by the Watergate hearings, this privilege does not extend to information germane to a criminal investigation.