Presumption of innocence the principle that a juror should vote to convict a criminal defendant only if the juror believes the accused to be guilty "beyond a reasonable doubt." A criminal defendant may not be convicted of a crime unless the government proves guilty beyond a reasonable doubt, without any burden on the accused to prove innocence. Since the authorities have the power to take away someone’s freedom, they are forced them to prove the case beyond a reasonable doubt and give the defendant the presumption of innocence.
The presumption of innocence is not articulated in the Constitution of the United States. However, it is a basic component of a fair trial, and the right to a fair trial is a fundamental liberty secured by the Fourteenth Amendment.