Glossary
Presumption of innocence
The fundamental principle that a criminal defendant is treated as innocent until the government proves guilt beyond a reasonable doubt. The defendant doesn't have to prove anything.
The presumption of innocence is one of the cornerstones of the U.S. criminal system. The defendant doesn't have to take the stand, doesn't have to call witnesses, doesn't have to put on any defense at all. They can sit silently and the prosecution still has to prove every element of every charge beyond a reasonable doubt.
In practice, defendants often do put on a defense: but they don't have to. The Fifth Amendment also gives them the right to remain silent without that silence being held against them at trial.
This presumption is why the burden of proof in criminal cases is so heavy. The system is structured to risk letting some guilty people go free rather than convict the innocent.