
Prelude: The Controlled Substances Act of 1970
Before Nixon officially declared war, Congress laid the legal foundation. The Comprehensive Drug Abuse Prevention and Control Act, signed into law on October 27, 1970, created the modern federal drug scheduling system. Title II of the act -- the Controlled Substances Act (CSA) -- established five schedules of controlled substances. Schedule I, reserved for drugs deemed to have "high potential for abuse" and "no currently accepted medical use," included heroin, LSD, psilocybin, mescaline, DMT, and cannabis. The scheduling of psychedelics as Schedule I effectively halted the clinical research that had been ongoing since the 1950s and would not resume in earnest for three decades.

Nixon's Declaration: June 17, 1971
On June 17, 1971, President Richard Nixon held a press conference in which he declared drug abuse "public enemy number one" and announced a comprehensive federal campaign to combat it. Nixon proposed the creation of a new federal agency to consolidate drug enforcement, increased funding for drug treatment and rehabilitation (which, notably, consumed two-thirds of the early drug-war budget), and pushed for mandatory minimum sentences and no-knock warrants.
In 1973, Nixon established the Drug Enforcement Administration (DEA) by executive order, merging the Bureau of Narcotics and Dangerous Drugs with other federal drug agencies into a single organization with a budget of $75 million and 1,470 special agents.
A controversial dimension of Nixon's motivations emerged decades later. In 1994, journalist Dan Baum interviewed John Ehrlichman, Nixon's domestic policy advisor, who reportedly stated: "The Nixon campaign in 1968, and the Nixon White House after that, had two enemies: the antiwar left and black people. We knew we couldn't make it illegal to be either against the war or black, but by getting the public to associate the hippies with marijuana and blacks with heroin, and then criminalizing both heavily, we could disrupt those communities." The quote, published by Baum in Harper's Magazine in 2016, has been disputed by Ehrlichman's family but is consistent with the administration's documented strategy.