Mandatory sentencing is a legal concept that requires offenders to serve a predefined term of imprisonment for certain crimes, usually serious or violent offenses. The sentences are produced through the legislature, not the judicial system, and judges are bound by law to impose them. The idea behind mandatory sentencing is that there are some crimes that are so heinous that there is no way to accept the offender back into the general population without first punishing them sufficiently. Mandatory sentencing laws often target "moral vices" such as alcohol, sex, and drugs, as well as crimes that threaten a persons livelihood.

Mandatory minimum sentencing laws require judges to administer prison terms of a particular length for people convicted of certain federal and state crimes. Most mandatory minimum sentences at the federal level apply to drug offenses, but Congress has also enacted them for other crimes, including certain gun and economic offenses. The primary purposes of modest mandatory prison terms are specific deterrence, which applies to already sanctioned offenders, and general deterrence, which aims to deter prospective offenders. However, mandatory minimums have been criticized for preventing judges from taking into account the individuals background and the circumstances of their offenses in the sentencing determination. They also disproportionately impact people of color, have caused prison populations to soar, and have led to overcrowding and exorbitant costs to taxpayers.

Research indicates that mandatory minimum sentencing effectively shifts discretion from judges to prosecutors, who decide what charges to bring against a defendant and can "stack the deck," which involves over-charging a defendant to get them to plead guilty. Opponents of mandatory sentencing argue that it is the proper role of a judge, not a prosecutor, to apply discretion given the particular facts of a case. They also tend to invoke sentencing disparities when choosing among a variety of statutes with different mandatory minimums.

In summary, mandatory sentencing is a legal concept that requires offenders to serve a predefined term of imprisonment for certain crimes. Mandatory minimum sentencing laws require judges to administer prison terms of a particular length for people convicted of certain federal and state crimes. While the primary purposes of modest mandatory prison terms are specific and general deterrence, mandatory minimums have been criticized for preventing judges from taking into account the individuals background and the circumstances of their offenses in the sentencing determination. They also disproportionately impact people of color, have caused prison populations to soar, and have led to overcrowding and exorbitant costs to taxpayers.