Perjury is the act of knowingly and intentionally lying about a material issue while under oath or falsifying an affirmation to tell the truth. It is considered a serious offense as it can be used to undermine the power of the courts, leading to miscarriages of justice. The definition of perjury varies by jurisdiction, but in general, it requires proof of more than just a false statement in a court proceeding or otherwise under oath. A person must make a false statement with an intent to defraud.
In the United States, perjury is a federal crime and is defined in two types. The first type involves statements made under oath and requires proof that the statement was made "under penalty of perjury," the person willfully made a statement that they did not believe to be true, and the subject matter of the statement was material. The second type of perjury involves making false statements in any matter within the jurisdiction of the executive, legislative, or judicial branch of the federal government.
To prove perjury, the elements of the crime must be met, including that the declarant took an oath to testify truthfully, that they willfully made a false statement contrary to that oath, that they believed the statement to be untrue, and that the statement related to a material fact. The question asked must have been unambiguous to prove that the witness gave a willfully false statement.
