March 18, 1839: Lin Tse-Hsu, the imperial Chinese commissioner in charge of suppressing the opium traffic, orders all foreign traders to surrender their opium. In response, the British send expeditionary warships to the coast of China, initiating the First Opium War.

March 14, 1937: Setting a judicial precedent important to drug policy, the US Supreme Court rules that machine guns can be controlled by first taxing them, then using the tax act to prohibit them. One month later Harry Anslinger, head of the Federal Bureau of Narcotics, introduces the Marijuana Tax Act to Congress.

March 19, 1983: Best known for her role in Just Say No, First Lady Nancy Reagan appears on the NBC sitcom Diff'rent Strokes, declaring: "Let me tell you a true story about a boy we'll call Charlie. He was only 14 and he was burned out on marijuana... One day, when his little sister wouldn't steal some money for him to go and buy some more drugs, he brutally beat her. The real truth is there's no such thing as soft drugs and hard drugs. All drugs are dumb... Don't end up another Charlie."

March 17, 1999: A report by the Institute of Medicine for the Office of National Drug Control Policy states that "there is no conclusive evidence that the drug effects of marijuana are causally linked to the subsequent abuse of other illicit drugs" and "scientific data indicate the potential therapeutic values of cannabinoid drugs for pain relief, control of nausea and vomiting, and appetite stimulation."

March 16, 2000: Patrick Dorismond, an unarmed security guard, is shot and killed by undercover New York City police officers who had unsuccessfully tried to sell him marijuana in a "buy-and-bust" operation. [The shooting was the third time in 13 months that New York City police officers dressed in plainclothes shot and killed an unarmed black man. Under Mayor Rudolph Giuliani, marijuana arrests rose from 720 in 1992, to 59,945 in the first eleven months of 2000.]

March 19, 2001: Mexican President Vicente Fox is quoted in the Associated Press: "[T]he day that the alternative of freeing the consumption of drugs from punishment comes, it will have to be done in the entire world because we are not going to win anything if Mexico does it, but the production and traffic of the drugs... to the United States continues. Thus, humanity will one day view it [legalization] as the best in this sense."

March 20, 2002: Reuters reports that British scientists found that motorists who smoke a cannabis joint retain more control behind the wheel than those who drink a glass of wine. Research from Britain's Transport Research Laboratory showed drivers found it harder to maintain constant speed and road position after drinking the equivalent of a glass of wine than after smoking a "spliff."