Burden of proof refers to the amount of evidence or proof required to adequately prove disputed facts in a court of law, and which party has the obligation to prove the disputed facts in order to prevail in court. In criminal prosecutions (cases) the government or prosecution has the burden to prove the accused defendant’s guilt beyond a reasonable doubt. This has been the standard for criminal prosecutions in the United States since at least 1880 when it was first mentioned by the U.S. Supreme Court. The determination of whether there is reasonable doubt as to an accused defendant’s guilt may be characterized by the question of whether there is an alternative explanation of the facts that seems plausible to the jurors.

In Missouri, as in all states across the United States, the burden of proof in criminal prosecutions lies with the government or prosecution. The prosecution must prove the defendant's guilt 'beyond a reasonable doubt,' which is the highest standard of proof in the American legal system. This standard has been a cornerstone of criminal law since it was articulated by the U.S. Supreme Court in the 1880s. It requires the jury to be convinced to a moral certainty that the defendant is guilty and that there is no other reasonable explanation for the evidence presented. If the jury finds that a plausible alternative explanation exists, or if they harbor reasonable doubt regarding the defendant's guilt, they are obliged to acquit. This principle is designed to protect the accused by ensuring that no one is convicted based on insufficient or ambiguous evidence.