1913–1915: California outlawed sale, cultivation, and possession of cannabis without prescription along with other narcotics.
1920s: Penalties for both sale and possession of marijuana hardened, punishable by fines and/or sentences ranging from 1⁄2 to 6 years for first-time offenses.
1937: U.S. Congress passes the Marihuana Tax Act effectively banning the possession and sale of marijuana with a prohibitive tax and potential imprisonment for evasion.
1970: U.S. Congress passes the Controlled Substances Act classifying marijuana as a Schedule I drug, the most restrictive categorization, with no accepted medical use.
1972, November: California voters reject Proposition 19, the California Marijuana Initiative, an attempt to decriminalize possession and cultivation for adults, by a 2–1 margin, 66.5% to 33.5%.
1972, December: State legislature passes the Drug Abuse Act (Chapter 2.5, California Penal Code 1000) giving judges the option of sending non-violent, first-time offenders to court-approved drug rehabilitation programs in lieu of conviction.
1975: California legislature passes SB 95, the Moscone Act, making possession of up to 1 ounce of marijuana for personal use a citable misdemeanor rather than a felony.
1996: California voters approve Proposition 215, the Compassionate Use Act (CUA) with 56% in favor, becoming the first state to legalize possession and cultivation of marijuana for medical use.
2000: Voters approve Proposition 36, the Substance Abuse and Crime Prevention Act, with 60% in favor, allowing first- and second-time non-violent marijuana possession offenders to be given a probationary sentence involving drug treatment programs rather than incarceration.
2010, September: Governor Schwarzenegger signs SB 1449, decriminalizing possession of up to 1 oz. to an infraction, punishable by a fine of $100. Like traffic tickets, appearance in court no longer necessary
2010, Nov: Voters reject Proposition 19, the Regulate, Control, and Tax Cannabis Act, to legalize recreational use, with 46.5% in favor.
2014, November: Voters pass Proposition 47, the Reduced Penalties for Some Crimes initiative, with 59.6% in favor, reclassifying some drug crimes and low-level offenses from felonies to misdemeanors.
2015, October: Governor Brown signs the Medical Marijuana Regulation and Safety Act, a three- bill package (SB 643, AB 266, AB 243) establishing the Bureau of Medical Marijuana Regulation, a regulatory body with oversight of physician recommendations, tracking movement of medical marijuana through the supply and distribution chain, and local and state licensing for dispensaries.