A presumption of innocence means that any defendant in a criminal trial is assumed to be innocent until they have been proven guilty. As such, a prosecutor is required to prove beyond a reasonable doubt that the person committed the crime if that person is to be convicted. To do so, proof must be shown for every single element of a crime. That being said, a presumption of innocence does not guarantee that a person will remain free until their trial has concluded. In some circumstances, a person can be held in custody.
The presumption of innocence is not guaranteed in the U.S. Constitution. However, through statutes and court decisions–such as the U.S. Supreme Court case of Taylor v. Kentucky–it has been recognized as one of the most basic requirements of a fair trial.
[Last updated in August of 2020 by the Wex Definitions Team]