Two years after former President Richard M. Nixon launched a war on drugs in 1971, calling substance use the nation's "public enemy No. 1," he made a startling admission during a meeting in the Oval Office. Speaking to a small group of aides and advisers at the White House in March 1973, Nixon said he knew that marijuana was "not particularly dangerous." Nixon, who had publicly argued that curbing drug use globally warranted an "all-out offensive," also privately expressed unease about the harsh punishments Americans were facing for marijuana crimes. The remarks were captured on the president's secret recording system amid a set of tapes that were only recently made widely available. The comments, on scratchy, sometimes hard-to-hear recordings, provide a surprising glimpse into the thinking of the president who implemented the federal government's drug classification system and decided that marijuana belonged in a category of substances deemed most prone to abuse and of no proven medical value. Over five decades, that designation has led to millions of arrests, which disproportionately affected Black people and hobbled efforts to rigorously study the therapeutic potential of cannabis. Experts on the Nixon years said that they were previously unaware of the recordings of Nixon speaking about marijuana and that the remarks were significant in light of the policies he had championed, which remain the backbone of today's drug laws.