March 30, 1961: The UN Single Convention on Narcotic Drugs is convened in New York City, the first of the three international treaties binding signatory nations into prohibitionist systems.

March 30, 1992: Bill Clinton, during the 1992 presidential campaign, says, "When I was in England I experimented with marijuana a time or two, and I didn't like it. I didn't inhale."

March 25, 1994: Retired minister Accelyne Williams dies of a heart attack when a SWAT team consisting of 13 heavily armed Boston police officers raids his apartment based on an incorrect tip by an unidentified informant. No drugs or guns were found in the apartment. An editorial in The Boston Globe later observed: "The Williams tragedy resulted, in part, from the 'big score' mentality of the centralized Boston Police Drug Control Unit. Officers were pumped up to seize machine guns in addition to large quantities of cocaine and a 'crazy amount of weed,' in the words of the informant."

March 24, 1998: House Speaker Newt Gingrich (R-GA) establishes the Speaker's Task Force for a Drug-Free America to design a World War II-style victory plan to save America's children from illegal drugs and achieve a Drug-Free America by 2002. Eleven years after the founding of the task force, in 2009, drugs continue to be widely available throughout the United States.

March 29, 2000: CNN reports that a multi-nation drug sweep known as Operation Conquistador nets 2,331 arrests, 4,966 kilograms of cocaine, 55.6 kilograms of heroin, and 362.5 metric tons of marijuana. The 17-day operation takes place in Panama, Colombia, Venezuela, Bolivia, Ecuador, Suriname, Trinidad and Tobago, Montserrat, Dominica, St. Kitts and Nevis, Antigua, Anguilla, St. Martin, British Virgin Islands, Barbuda, Grenada, Barbados, St. Vincent and the Grenadines, St. Lucia, Aruba, Curacao, Jamaica, Haiti, Dominican Republic, and Puerto Rico. Drug availability is not reduced in the operation's wake.

March 25, 2002: The Maryland House of Delegates overwhelmingly approves H.B. 1222, the Darrell Putman Compassionate Use Act, which removes criminal penalties for the medical use of marijuana.

March 26, 2002: A unanimous US Supreme Court rules that public housing tenants can be evicted for any illegal drug activity by household members or guests, even if they did not know about it.

March 28, 2002: Federal Judge Emmet G. Sullivan rules that the Barr Amendment, which blocks the District of Columbia from considering a medical marijuana voter initiative, infringes on First Amendment rights.

March 28, 2003: The Hemp Industries Association, several hemp food and cosmetic manufacturers and the Organic Consumers Association petition the federal Ninth Circuit to again prevent the DEA from ending the legal sale of hemp seed and oil products in the US.