Colorado and Washington passed referendums legalizing marijuana for recreational use, becoming the first states in the country to legalize the drug, according to ABC News.
ABC News projects that a similar measure in Oregon failed to garner enough support to pass.
The initiatives would allow marijuana to be cultivated and for special stores to sell up to an ounce to individuals 21 and older.
In Colorado specifically, the Amendment 64 makes changes to state law to allow for commercial production and sale. Newsweek reported that business – including big tobacco – has been gearing up for the change.
"It's unprecedented," Jonathan Caulkins, a Carnegie Mellon University professor, told The Denver Post. He said the change would put Colorado to the left of the Netherlands when it comes to marijuana policy.
It could also impact Mexico.
A report found that legalizing marijuana would cut the cartels' income by $1.37 billion, or 23 percent of its $6 billion in sales in the United States. Legalization in Colorado potentially represents a similar decline.
"I think it's a good step," said Brandon Romney, Mitt Romney's third cousin who lives in Mexico near the U.S.-Mexico border. "Eventually the U.S. and Mexico will have to move toward decriminalization. So, better sooner than later."
In Massachusetts, voters approved a ballot measure to allow medical marijuana use for patients suffering from debilitating medical conditions like cancer or Parkinson's disease. Massachusetts became the 18th state to legalize it – joining Colorado, Washington, Oregon, and the District of Columbia.
Arkansas also voted on whether to authorize marijuana for medical uses. However, early results indicate it is unlikely to pass.
Both laws in Colorado and Washington represent a challenge to federal law, which considers it as a Schedule 1 drug – its strictest classification. It is unclear what will be the federal governments reaction.
In one scenario, according to reporting by the Huffington Post, "even that financial win for Colorado could disappear if Congress decided to 'punish' Colorado by withholding federal highway funds."