criminal law Criminal law is the body of law that relates to crime. It prescribes conduct perceived as threatening, harmful, or otherwise endangering to the property, health, safety, and moral welfare of people inclusive of one's self. Most criminal law ...

, an overt act is the one that can be clearly proved by

evidence Evidence for a proposition is what supports this proposition. It is usually understood as an indication that the supported proposition is true. What role evidence plays and how it is conceived varies from field to field. In epistemology, evidenc ...

and from which criminal intent can be inferred, as opposed to a mere intention in the mind to commit a

crime In ordinary language, a crime is an unlawful act punishable by a state or other authority. The term ''crime'' does not, in modern criminal law, have any simple and universally accepted definition,Farmer, Lindsay: "Crime, definitions of", in C ...

. Such an act, even if innocent ''per se'', can potentially be used as evidence against someone during a

trial In law, a trial is a coming together of parties to a dispute, to present information (in the form of evidence) in a tribunal, a formal setting with the authority to adjudicate claims or disputes. One form of tribunal is a court. The tribun ...

to show participation in a crime. For instance, the purchase of a

ski mask A balaclava, also known as a balaclava helmet or ski mask, is a form of cloth headgear designed to expose only part of the face, usually the eyes and mouth. Depending on style and how it is worn, only the eyes, mouth and nose, or just the fron ...

, which can conceal identity, is generally a legal act but may be an overt act if it is purchased in the planning of a

bank robbery Bank robbery is the criminal act of stealing from a bank, specifically while bank employees and customers are subjected to force, violence, or a threat of violence. This refers to robbery of a bank branch or teller, as opposed to other bank- ...

. The term is more particularly employed in cases of

treason Treason is the crime of attacking a state authority to which one owes allegiance. This typically includes acts such as participating in a war against one's native country, attempting to overthrow its government, spying on its military, its diplo ...

, which must be demonstrated by some overt or open act in some jurisdictions. This rule was enacted in the law of England ''(see the

Treason Act 1547 The Treason Act 1547 (1 Ed. 6 c.12) was an Act of the Parliament of England. It is mainly notable for being the first instance of the rule that two witnesses are needed to prove a charge of treason, a rule which still exists today in the United S ...

)'', and was later adopted by the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

in Article III, Section 3 of the United States Constitution, which provides that "No Person shall be convicted of Treason unless on the

Testimony In law and in religion, testimony is a solemn attestation as to the truth of a matter. Etymology The words "testimony" and "testify" both derive from the Latin word ''testis'', referring to the notion of a disinterested third-party witness. ...

of two

Witness In law, a witness is someone who has knowledge about a matter, whether they have sensed it or are testifying on another witnesses' behalf. In law a witness is someone who, either voluntarily or under compulsion, provides testimonial evidence, e ...

es to the same overt Act, or on Confession

in open Court In open court is a legal term in the United States defined by the appearance by a party or their attorney in a public court session such as during a public trial. Normally, the public may be present at trials, hearings and similar routine matt ...

." In '' Cramer v. United States'', the

Supreme Court A supreme court is the highest court within the hierarchy of courts in most legal jurisdictions. Other descriptions for such courts include court of last resort, apex court, and high (or final) court of appeal. Broadly speaking, the decisions of ...

ruled that "every act, movement, deed, and word of the defendant charged to constitute treason must be supported by the testimony of two witnesses." In ''Haupt v. United States'' (330 U.S. 631), however, the Supreme Court found that two witnesses are not required either to prove intent or to prove that an overt act is treasonable. The two witnesses, according to that decision, are required to prove only that the overt act occurred."The Haupt Case
at Cornell Law School website In some jurisdictions, a

defendant In court proceedings, a defendant is a person or object who is the party either accused of committing a crime in criminal prosecution or against whom some type of civil relief is being sought in a civil case. Terminology varies from one jurisd ...

cannot be convicted of

criminal conspiracy In criminal law, a conspiracy is an agreement between two or more persons to commit a crime at some time in the future. Criminal law in some countries or for some conspiracies may require that at least one overt act be undertaken in furtherance ...

unless an overt act is proved.

References

Criminal law {{law-stub