While lying to police officers who are casually questioning you could lead to obstruction of justice charges, lying under oath is a much more serious offence. Also known as perjury, this crime is only applicable to relevant lies you tell after swearing an oath to court officials to tell the truth. Perjury can result in criminal charges that could lead to fines or prison time.
Lying vs. Perjury
Being put under oath is a very specific legal process. It must be done in the presence of representatives of the court, and the entire process must be carefully transcribed. This includes the statements of the court officials, the questions from the lawyers and the responses you give when under oath. Lying under oath is something that can occur when you have taken an oath to tell the truth before a court of law, grand jury or during a deposition.
The American justice system is premised on the veracity of the testimony individuals give in court. Because judges and juries must make their decisions based on sworn testimony, perjury can subvert the justice system. Because of the serious nature of this crime, the punishment can be equally serious. Depending on if the case is being tried at the state or federal level, the sentence can include a heavy fine and jail time. At the federal level, this can be up to five years.
If you are suspected of perjury, then it is a crime in and of itself for which you will face a criminal trial. This trial will determine both if you are guilty of perjury or not, and if you are guilty what the penalty will be. As with any other crime, you will be presumed innocent until proven guilty in the course of this trial. The trial will have to prove that you lied, and that your lies meet the qualifications for perjury.
The crime of perjury requires that you wilfully lied about the information that was pertinent to the lawyer's line of questioning. The prosecution has to prove that your lie was one of purposefully thwarting the justice system by purposefully providing false information. Errors of memory do not qualify as perjury. Additionally, the lie must be relevant to the case. If you lie about your age, for example, when your age is not relevant to the case, then the lie does not necessarily rise to the extent of perjury. As with all legal matters, you should consult with your lawyer on all charges you do or may face for expert advice on your particular situation.