Domestic drug enforcement involves controlled substances that are prohibited and controlled substances that are diverted from their intended medical purpose. The federal government prohibits the manufacturing, distribution, and possession of many intoxicating substances that are solely intended for recreational use (notable exceptions are alcohol and tobacco); however, the federal government also allows for and controls the medical use of many intoxicants. Federal authority to control these substances primarily resides with the Attorney General of the United States. In 1970, Congress found that many drugs have a legitimate medical purpose and are necessary to sustain the health and welfare of the American people; however, Congress also found that illegal actions involving and improper use of these drugs have a detrimental effect on the health and welfare of the American people. Among other findings that Congress included in the Controlled Substances Act (CSA; P.L. 91-513), it found that federal control of drug trafficking that occurs within states (i.e., intrastate drug trafficking) is essential to the effective control of drug trafficking that occurs across state lines (i.e., interstate drug trafficking). Congress relies on its power to regulate interstate commerce as a basis for drug control. In order to restrict and reduce availability of illicit drugs in the United States, a practice referred to as "supply reduction," the federal government emphasizes domestic drug enforcement. As a result of enforcement actions, illicit drugs are more difficult, expensive, and risky to obtain. Federal law enforcement agencies cooperate with state and local agencies to dismantle and disrupt criminal organizations involved in illicit domestic drug production and distribution. In practice, federal law enforcement agencies generally target large drug trafficking organizations rather than low-level drug offenders. Over the last several years, Congress and the Administration have confronted multiple domestic drug enforcement issues. These issues include state marijuana legalization, prescription drug and heroin abuse, and evolving synthetic drugs. Synthetic compounds have been created across the various classes of drugs, and different synthetic drugs have gained and lost popularity among illicit drug users over the last several decades. This report reviews federal domestic drug enforcement. First, it provides a history and background of drug enforcement in the United States including how drugs came under the control of federal justice authorities and how legislation and administrative actions changed domestic drug enforcement. It then provides a brief overview of drug enforcement in the United States and summarizes U.S. drug policy. Finally, the report presents trends in federal drug enforcement and concludes with a discussion of drug enforcement issues going forward. This section outlines historic development and major changes in federal drug enforcement to help provide an understanding of how and why certain laws and policies were implemented and how these developments and changes shaped current drug enforcement policy. Both recreational and medical use of drugs, including cocaine and opium, were popular in the 19 th century, but the federal government was not involved in restricting or regulating their distribution and use. During this time, the federal government did not have any agencies that regulated medical and pharmaceutical practice, and doctors freely prescribed cocaine and morphine as treatment for pain. By the end of the 19 th century, abuse of these drugs was a significant social issue, and public concern was growing. Scholars identify the separation of federal and state power as a major reason for an unregulated U.S. drug market in the 19 th century. Attempts to establish federal control over drugs were met with strong opposition from patent medicine firms and state officials. Federal control of drugs began to take shape in the early 20 th century. In response to growing levels of drug abuse, the federal government sought to regulate and control drugs through taxation. The Harrison Narcotics Act of 1914 (Harrison Act; P.L. 63-223), among other things, required importers, manufacturers, and distributors of cocaine and opium to register with the U.S. Department of the Treasury (the Treasury), pay a special tax on these drugs, and keep records of each transaction. Under the Harrison Act, practitioners were authorized to prescribe opiates and cocaine; however, the law was subject to interpretation. The Treasury viewed patient drug maintenance using these substances as beyond medical scope, and many physicians were arrested, prosecuted, and jailed. Under authority of the Harrison Act, the Narcotic Division of the Internal Revenue Bureau closed down state and city narcotic clinics and sent drug violators to federal penitentiaries. Enforcement agents were referred to as "narcs." Ultimately, physicians stopped prescribing drugs covered under the Harrison Act, thereby sending users to the black market to seek out these substances. During the 1920s, narcotic enforcement was closely tied to Prohibition enforcement. In 1930, Prohibition enforcement was transferred to the Department of Justice while a standalone federal agency, the Federal Bureau of Narcotics (FBN), was established within the Treasury to handle narcotic enforcement. During Prohibition, a new recreational drug—marijuana—had quickly become unpopular with law enforcement, especially in the southwestern United States. As Prohibition ended, marijuana caught the attention of Congress and the FBN. Until 1937, the growth and use of marijuana was legal under federal law. During the course of promoting federal legislation to control marijuana, Henry Anslinger, the first commissioner of the FBN, and others submitted testimony to Congress regarding the evils of marijuana use, claiming that it incited violent and insane behavior. Of note, Commissioner Anslinger had informed Congress that "the major criminal in the United States is the drug addict; that of all the offenses committed against the laws of this country, the narcotic addict is the most frequent offender." The federal government unofficially banned marijuana under the Marihuana Tax Act of 1937 (MTA; P.L. 75-238). The MTA imposed a strict regulation requiring a high-cost transfer tax stamp for every sale of marijuana. These stamps, however, were rarely issued by the federal government. Shortly after passage of the MTA, all states made the possession of marijuana illegal. Enforcement of drug laws was primarily the responsibility of local police, and the FBN occasionally assisted with enforcement. Due to limited and reduced appropriations during the Great Depression, which began in the United States after the stock market crash of 1929 and lasted through the 1930s, the FBN budget and the number of narcotic agents declined and remained low for years. Publicity and warnings of the dangers of narcotics, in particular marijuana, became methods of drug control for the FBN. In seeking federal control of marijuana and uniform narcotic laws, Commissioner Anslinger made personal appeals to civic groups and legislators and pushed for, and received, editorial support in newspapers; many newspapers maintained a steady stream of anti-marijuana propaganda in the 1930s. Over the next several decades, Congress continued to pass drug control legislation and further criminalized drug abuse. For example, the Boggs Act (P.L. 82-255), passed in 1951, established mandatory prison sentences for some drug offenses while the 1956 Narcotic Control Act (P.L. 84-728) further increased penalties for drug offenses and established the death penalty as punishment for selling heroin to youth. The FBN continued to enforce federal narcotic laws and support local enforcement while the agency remained relatively unchanged until the 1960s. Support for severe punishment for drug offenses, however, waned by this point. Organizations, including the American Bar Association, began to speak out against strict punishments for drug offenders while federal support for a medical approach to drug abuse grew. For instance, methadone maintenance became an acceptable and common treatment for heroin dependence. In 1963, the Presidential Commission on Narcotic and Drug Abuse (the 1963 Presidential Commission) issued a report recommending more funds for narcotic research, less strict punishment for drug offenses, and the dismantling of the FBN. Congress also began to support the medical approach to addressing drug abuse. It heeded the recommendations of the 1963 Commission and created the Bureau of Drug Abuse Control within the Department of Health, Education, and Welfare and provided for civil commitment of some drug addicted federal detainees. In the Narcotic Addict Rehabilitation Act, Congress declared its support for rehabilitation through treatment: It is the policy of the Congress that certain persons charged with or convicted of violating Federal criminal laws, who are determined to be addicted to narcotic drugs, and likely to be rehabilitated through treatment, should, in lieu of prosecution or sentencing, be civilly committed for confinement and treatment designed to effect their restoration to health, and return to society as useful members. While there was a great deal of attention paid to the medical approach to preventing and responding to drug abuse in the 1960s, there was also strong emphasis on law enforcement. The 1963 Presidential Commission, among other findings, had recommended increasing federal drug enforcement personnel and transferring drug enforcement functions from the Treasury to the Department of Justice (DOJ). Subsequently, Congress shifted the constitutional basis for drug control from its taxing authority to its power to regulate interstate commerce, and in 1968 the FBN merged with the Bureau of Drug Abuse Control and was transferred to DOJ. In 1969 President Nixon responded to rising drug abuse, in particular heroin abuse, by making the reduction of drug use one of his top priorities upon taking office. Several years later President Nixon would declare a war on drugs. President Nixon's war on drugs involved greater emphasis on law enforcement. He also enhanced international efforts and made a successful push to curb opium production in Turkey. In his efforts to enhance federal control of drugs, Nixon pushed for passage of comprehensive federal drug laws. The Controlled Substances Act (CSA), enacted as Title II of the Comprehensive Drug Abuse Prevention and Control Act of 1970 (P.L. 91-513), placed the control of select plants, drugs, and chemical substances under federal jurisdiction. Congress passed this legislation, in part, to replace previous federal drug laws with a single comprehensive statute. The CSA established the statutory framework through which the federal government regulates the lawful production, possession, and distribution of controlled substances.