The presumption of innocence, an ancient tenet of Criminal Law, is actually a misnomer. According to the U.S. Supreme Court, the presumption of the innocence of a criminal defendant is best described as an assumption of innocence that is indulged in the absence of contrary evidence (Taylor v. Kentucky, 436 U.S. 478, 98S. Ct. 1930, 56 L. Ed. 2d 468 ). It is not considered evidence of the defendant’s innocence, and it does not require that a mandatory inference favorable to the defendant be drawn from any facts in evidence.
In practice the presumption of innocence is animated by the requirement that the government prove the charges against the defendant Beyond a Reasonable Doubt. This due process requirement, a fundamental tenet of criminal law, is contained in statutes and judicial opinions. The requirement that a person suspected of a crime be presumed innocent also is mandated in statutes and court opinions. The two principles go together, but they can be separated.
The Supreme Court has ruled that, under some circumstances, a court should issue jury instructions on the presumption of innocence in addition to instructions on the requirement of proof beyond a reasonable doubt (Taylor v. Kentucky). A presumption of innocence instruction may be required if the jury is in danger of convicting the defendant on the basis of extraneous considerations rather than the facts of the case.
The presumption of innocence principle supports the practice of releasing criminal defendants from jail prior to trial. However, the government may detain some criminal defendants without bail through the end of trial. The Eighth Amendment to the U.S. Constitution states that excessive bail shall not be required, but it is widely accepted that governments have the right to detain through trial a defendant of a serious crime who is a flight risk or poses a danger to the public. In such cases the presumption of innocence is largely theoretical.
Aside from the related requirement of proof beyond a reasonable doubt, the presumption of innocence is largely symbolic. The reality is that no defendant would face trial unless somebody—the crime victim, the prosecutor, a police officer—believed that the defendant was guilty of a crime. After the government has presented enough evidence to constitute Probable Cause to believe that the defendant has committed a crime, the accused need not be treated as if he or she was innocent of a crime, and the defendant may be jailed with the approval of the court.
Nevertheless, the presumption of innocence is essential to the criminal process.The mere mention of the phrase presumed innocent keeps judges and juries focused on the ultimate issue at hand in a criminal case: whether the prosecution has proven beyond a reasonable doubt that the defendant committed the alleged acts. The people of the United States have rejected the alternative to a presumption of innocence—a presumption of guilt—as being inquisitorial and contrary to the principles of a free society.