Federal mandatory minimum sentencing statutes (mandatory minimums) demand that execution or incarceration follow criminal conviction. Among other things, they cover drug dealing, murdering federal officials, and using a gun to commit a federal crime. They have been a feature of federal sentencing since the dawn of the republic. They circumscribe judicial sentencing discretion, although they impose few limitations upon prosecutorial discretion, or upon the President's power to pardon. They have been criticized as unthinkingly harsh and incompatible with a rational sentencing guideline system; yet they have also been embraced as hallmarks of truth in sentencing and a certain means of incapacitating the criminally dangerous. This is a brief overview of federal statutes in the area and a discussion of some of the constitutional challenges they have faced. Mandatory minimums come in many stripes, including some whose status might be disputed. The most widely recognized are those that demand that offenders be sentenced to imprisonment for "not less than" a designated term of imprisonment. Some are triggered by the nature of the offense, others by the criminal record of the offender. A few members of this "not less than" category are less "mandatory" than others, because Congress has provided a partial escape hatch or safety valve. For example, several of the drug-related mandatory minimums are subject to a "safety valve" for small time, first time, non-violent offenders that may render their minimum penalties less than mandatory, or at least less severe. Still others can be avoided at the behest of prosecution for a defendant's substantial assistance against his cohorts. Some of the other "not-less-than" mandatory minimums purport to permit the court to sentence an offender to a fine rather than to a mandatory term of imprisonment. A second generally recognized category of mandatory minimums consists of the flat or single sentence statutes, the vast majority of which call for life imprisonment. Closely related are the capital punishment statutes that require imposition of either the death penalty or imprisonment for life, or death or imprisonment either for life or for some term of years. The "piggyback" statutes make up a third class. The piggyback statutes are not themselves mandatory minimums but sentence offenders by reference to underlying statutes including those that impose mandatory minimums. Until the Supreme Court intervened in Booker v. United States to eliminate the binding effect of the Sentencing Guidelines, the final and least obvious group was comprised of statutes whose violation resulted in the imposition of a mandatory minimum term of imprisonment by operation of law, or more precisely by operation of the Sentencing Reform Act and the Sentencing Guidelines issued in its name. After Booker and the line of cases that followed, the Guidelines cannot fairly be characterized as a source of mandatory minimum sentences, although they continue to tilt heavily toward incarceration. Mandatory minimums have been with us from the beginning. In fact, the history of our criminal sentencing practices is the story of increased reliance upon judicial or administrative discretion in order to mute the law's severity in individual cases, followed by increased limitations on such discretion in order to curb the resulting arbitrary and discriminatory disparities in punishment. It is a saga in which "competing theories of mandatory and discretionary sentencing have been in varying degrees of ascendancy or decline." Severity and a want of discretion marked the early criminal law. The sentence which followed a felony conviction was death; except in rare instances no other punishment could be imposed. Over time the courts were given some discretion over sentencing, but the choices were hardly lenient; and corporal punishment and banishment were common. Yet even early on there were efforts to ease the law's severity. Both the accused and the convicted could be pardoned at the King's will. While Parliament regularly increased the number of crimes, it often replaced common law capital offenses with statutory crimes defined as misdemeanors or subject to the benefit of clergy. The result was the same in either case, a reduced number of capital offenses. In our own country, state legislatures drastically curtailed the number of capital offenses soon after the Revolution. When the first Congress assembled, it enacted several mandatory minimums, each of them a capital offense. The 19 th century, however, witnessed the appearance of a host of discretionary schemes designed to ease the harshness of criminal law in individual cases. The courts could suspend sentence and were vested with broad authority in the selection of those sentences they chose to impose. Probation and parole were born and became prominent. By late in the century at the federal level, the number of mandatory capital offenses had been reduced, and while the number of mandatory minimums had increased, most federal criminal statutes merely established a maximum penalty and left to the discretion of the courts the sentences to be imposed within the maximum. The 1909 federal criminal code revision eliminated most mandatory minimums; soon thereafter federal prisoners were made eligible for parole after service of a third of their sentences (after 15 years in the case of prisoners with life sentences); and federal courts shortly thereafter received the authority to suspend the imposition or execution of sentence and impose probation. The 1948 federal criminal code revision took much the same tack as its predecessor: it eliminated many, but not all, of the "not-less-than" mandatory minimums and continued in place most of the "flat" sentence mandatory minimums. By mid-20 th century, a well-respected commentator could observe that "[t]he individualization of penal dispositions, principally through the institutions of the indeterminate sentence, probation, and parole, is a development whose value few would contest." The contest was joined soon thereafter. Driven by concerns that broad discretion had led to rootless sentencing, unjustifiable in its leniency in some instances and in its severity in others, legislative bodies moved to curtail discretionary sentencing on several fronts. Determinate sentencing, sentencing commissions and guidelines, and mandatory minimum sentences became more prevalent. Parole and probation were abolished or greatly restricted in several jurisdictions. The Sentencing Reform Act of 1984 brought this trend to the federal criminal justice system. It repealed the authority of the federal courts to suspend criminal sentences. It abolished federal parole. It created a sentencing guideline system, applicable within the statutory maximum and minimum penalties established by Congress that tightly confined the sentencing discretion of federal judges. The armed career criminal, three strikes, and several of the other prominent drug, child pornography, and gun related mandatory minimums followed in the ensuing years. Upon motion of the Government, the court shall have the authority to impose a sentence below a level established by statute as a minimum sentence so as to reflect a defendant's substantial assistance in the investigation or prosecution of another person who has committed an offense. Such sentence shall be imposed in accordance with the guidelines and policy statements issued by the Sentencing Commission pursuant to section 994 of title 28, United States Code. This substantial assistance provision was enacted with little fanfare in the twilight of the 99 th Congress as part of the massive Anti-Drug Abuse Act of 1986, legislation which established or increased a number of mandatory minimum sentencing provisions. The section passed between the date authorizing the Sentencing Guidelines and the date they became effective. Rather than replicate the language of section 3553(e), the Guidelines contain an overlapping section which authorizes a sentencing court to depart from the minimum sentence called for by the Guidelines. As a general rule, a defendant is entitled to a sentence below an otherwise applicable statutory minimum under the provisions of §3553(e) only if the government agrees. The courts have acknowledged that due process or equal protection or other constitutional guarantees may provide a narrow exception. "Thus, a defendant would be entitled to relief if a prosecutor refused to file a substantial-assistance motion, say, because of the defendant's race or religion." A defendant is entitled to relief if the Government's refusal constitutes a breach of its plea agreement. A defendant is also "entitled to relief if the prosecutor's refusal to move was not rationally related to any legitimate Government end." Some courts have suggested that a defendant is entitled to relief if the prosecution refuses to move under circumstances that "shock the conscience of the court," or that demonstrate bad faith, or for reasons unrelated to substantial assistance. A majority of the judges who answered the Sentencing Commission's survey agreed that relief under §3553(e) should be available even in the absence of motion from the prosecutor. A motion under §3553(e) for a sentence beneath the mandatory minimum and a motion under U.S.S.G. §5K1.1 for a sentence beneath the applicable Sentencing Guideline range are not the same. Thus, a motion under §5K1.1 will ordinarily not be construed as a motion under §3553(e). Any sentence imposed below the statutory minimum by virtue of section 3553(e) must be based on the extent of the defendant's assistance; it may not reflect considerations unrelated to such assistance. It has been suggested that a court may use the section 5K1.1 factors for that determination, that is, "(1) the court's evaluation of the significance and usefulness of the defendant's assistance, taking into consideration the government's evaluation of the assistance rendered; (2) the truthfulness, completeness, and reliability of any information or testimony provided by the defendant; (3) the nature and extent of the defendant's assistance; (4) any injury suffered, or any danger or risk of injury to the defendant or his family resulting from his assistance; [and] (5) the timeliness of the defendant's assistance." The substantial assistance exception makes possible convictions that might otherwise be unattainable. Yet, it may also lead to "inverted sentencing," that is, a situation in which "the more serious the defendant's crimes, the lower the sentence – because the greater his wrongs, the more information and assistance he had to offer to a prosecutor"; while in contrast the exception is of no avail to the peripheral offender who can provide no substantial assistance.