The presumption of innocence is the legal mandate that a person is innocent until proven guilty in a court of law. It requires that the accuser prove the case being asserted against the defendant rather than require the defendant to prove that the accuser is wrong. It is a constitutional right for Americans to have the presumption of innocence. If a person is tried for a crime and not convicted, it is a necessity that the person is treated as though they are innocent.
This requirement is based on the fact that it is easier to keep a good name than it is to repair a bad one and that a person would have a right not to have things said about them which could later be proven to be untrue even when there is a possibility or a probability that the assertion is in fact true. This requirement exists within English law as well as American law. It also exists in other countries as well.