Singer (D) was charged with mail fraud. At trial, D attempted to waive a trial by jury. The trial court was willing to approve the waiver, but the government (P) refused to consent. D was convicted. D appealed, claiming that the Constitution gives a defendant in a federal criminal case the right to waive a jury trial whenever he believes such action to be in his best interest, regardless of whether the prosecution and the court are willing to acquiesce.