The first national regulation was the Marihuana Tax Act of 1937. Cannabis was officially outlawed for any use (medical included) with the passage of the 1970 Controlled Substances Act (CSA). Multiple efforts to reschedule cannabis under the CSA have failed, and the U.S. Supreme Court ruled in United States v.

When did weed become illegal?

Marijuana has been illegal at the federal level since 1937. The federal government continues to spell marijuana and cannabis "marihuana" and classifies it as a Schedule 1 controlled substance, alongside hallucinogens​, LSD, peyote, heroin, most opiates, methaqualone, and ecstasy.

Why was weed illegal in the first place?

For Western states, a driving reason was a fear of Mexican immigrants who used the plant. In Eastern states, it was fear of African Americans and jazz musicians who used cannabis to “take advantage of white women.” Making marijuana illegal was essentially a way to outlaw being an immigrant or not white.