The U.S. Sentencing Commission’s guidelines have failed to win acceptance by federal judges and other practitioners and have not been shown to have reduced sentencing disparities in the federal courts. Many state guidelines systems by contrast have been accepted by affected practitioners and have reduced sentencing disparities. The federal guidelines were unpopular in 1987 when they were first implemented and are more unpopular today because of their rigidity, harshness, and complexity. The guidelines should be substantially revised or repealed.