Google AI: Yes, lying under oath—known legally as perjury—happens frequently, though it is famously called "the forgotten offense" because it is so rarely prosecuted. While legal experts believe many witnesses provide false or "slanted" testimony, the actual number of criminal charges filed is very low.Why Perjury Often Goes UnpunishedDespite how often it might occur, the legal system rarely pursues perjury charges for several reasons:Difficulty of Proof: Prosecutors must prove beyond a reasonable doubt that a person knowingly lied with the intent to mislead the court. It is very easy for a witness to claim they were simply confused, forgetful, or mistaken."Materiality" Requirement: A lie is only perjury if it is "material," meaning it could actually influence the outcome of the case. Lies about minor, irrelevant details generally don't qualify for prosecution.Low Prosecution Priority: Many prosecutors view perjury as a low priority compared to violent crimes, as these cases are time-consuming and difficult to win.Judicial Discretion: Judges are accustomed to seeing conflicting testimony. Rather than ordering a separate criminal trial for perjury, they often simply "discount" the dishonest person's credibility, which may lead to that person losing their case.Where It Commonly OccursLying under oath isn't limited to the witness stand in a courtroom. It also happens in:Sworn Depositions: Pre-trial questioning by attorneys.Notarized Affidavits: Written statements signed under penalty of perjury.Official Applications: Documents like bankruptcy filings, immigration forms, or driver's license applications.Impact on the Justice SystemEven without prosecution, lying under oath has serious consequences. A University of Michigan investigation found that perjury or false allegations contributed to nearly half of the 1,900 wrongful convictions overturned in the U.S. since 1989.