Marijuana is legal for adults over the age of 21 in 9 states, and medical marijuana is legal in 31.
- Marijuana legalization is on the ballot in four states in Tuesday's midterm elections.
- Recreational marijuana is already legal in nine states and medical marijuana is legal in 31 states.
- A 2017 Gallup poll showed that 64% of Americans support legalization.
Michigan and North Dakota are weighing measures to legalize recreational marijuana for all adults, while bright-red Utah and Missouri residents are voting on medical marijuana measures.
Oklahoma voted to legalize medical marijuana earlier this year. Residents voted 56-43% in support of the ballot initiative, which is one of the most permissive medical marijuana laws in the US.
Nine states and Washington, DC, have legalized marijuana for recreational use — no doctor's letter required — for adults over the age of 21.
In January, Vermont became the first state to legalize marijuana through the legislature, rather than a ballot initiative, when the governor signed the bill into law.
Marijuana prohibition began 80 years ago when the federal government put a ban on the sale, cultivation, and use of the cannabis plant. It remains illegal on the federal level.
Despite the efforts of Attorney General Jeff Sessions, who has been on a crusade to stamp out legal marijuana since his appointment, the industry is exploding.
Legal marijuana sales exploded to $9.7 billion in North America in 2017, according to a report from Arcview Market Research and BDS Analytics. That represents a 33% increase over 2016, shattering previous expectations about how quickly the marijuana industry could grow in the face of federal prohibition.
The report also predicted the legal marijuana market will reach $24.5 billion in sales — a 28% annual compound growth rate — by 2021, as more state-legal markets come online.
Read more of Business Insider's cannabis industry coverage:
- The top 12 venture-capital firms making deals in the booming cannabis industry that's set to skyrocket to $75 billion
- The CEO of the biggest cannabis company in the US reveals what's next following a $682 million acquisition
- Hedge fund legend Leon Cooperman is investing in the marijuana industry — and it's another sign the sector is heating up
- Famous short seller Andrew Left is creating a cannabis fund. He explains why the market's not in a bubble, but does need to 'chill out'
- 'The new avocado toast': A former Coca-Cola and AB InBev executive reveals why every food and beverage boardroom needs to be talking about cannabis
- Some of the hottest companies in the booming cannabis sector are going on hiring sprees — and it shows how competition among the biggest players is ramping up