On the other hand, a string of defeats would signal public unease about condoning the use of an intoxicating substance that isn't tobacco or alcohol. Defeats would suggest that opponents' longstanding criticisms of the legal marijuana industry are making inroads among voters.
As campaigning shifts into high gear in the fall, here's a rundown of where marijuana will be on the ballot in November -- and how those contests are shaping up.
California -- Recreational marijuana
A "yes" on weed in the world's sixth-largest economy would loom large in the marijuana debate, making marijuana legal along the entire West Coast.
California is home to nearly 40 million people and an existing $2.7 billion market in medical marijuana. Legalization of recreational marijuana could cause that industry to swell to $6 billion or more by 2020, according to ArcView Research, a marijuana industry research firm. That kind of money is already drawing the interest of businesses and investors, who could leverage their newfound legal lobbying clout to pressure Congress and other states to relax restrictions on marijuana sales and use.
Polls have shown the legalization measure drawing the support of 60 percent -- or more -- of voters, making it perhaps the marijuana initiative most likely to pass this fall. Legalization has been endorsed by some high-profile state and national politicians, as well as the California Democratic Party, the ACLU and NAACP of California, and the California Medical Association. It's opposed by a number of law enforcement groups and some politicians, including Sen. Dianne Feinstein (D-Calif.).
Supporters of the legalization measure also hold a huge fundraising advantage over opponents. According to Ballotpedia, supporters had roughly $11.5 million in cash on hand as of Aug. 16, compared to opponents' $186,000.
Nevada -- Recreational marijuana
While home to only 2.8 million people, legal weed in Nevada could have outsize national impact due to Las Vegas's draw as a tourism destination -- 40 million visitors per year.
Still, there's a lot less money in play in Nevada than there is in California -- supporters of legalization have a little more than $1 million in cash on hand, while opponents have zero, according to the latest campaign finance disclosures.
A late infusion of Adelson cash in Nevada could tip the scale of public support for the legalization measure there. A July poll found that 50 percent of Nevada voters supported the measure, while 41 percent opposed it.
Arizona -- Recreational marijuana
Arizona is the third act of the marijuana legalization trilogy playing out in the West this November. It's also the state giving marijuana proponents their toughest fight -- a July poll found that only 39 percent of likely voters support the measure, while 53 percent oppose.
The measure is not fundamentally different from other legalization bills on November ballots. But Arizona has different demographics than its neighbors to the north and west. The state has voted Republican in every presidential election since 1996, and Republicans are less likely to support marijuana legalization than other Americans.
Massachusetts -- Recreational marijuana
Massachusetts, on the other hand, is one of the deepest blue states in the nation, but voters there don't seem to be warming up to the legalization measure on their ballot this fall. Just 41 percent said they'd vote for it in July, down from the mid-to-high-50s a few months earlier.
Some elected officials have been campaigning fiercely against the state's marijuana measure, including Governor Charlie Baker. In March, he joined the state attorney general and Boston's mayor to pen an op-ed in the Boston Globe that was highly critical of legalization efforts. Soon after it published, a state Senate committee released a report detailing how lawmakers could blunt the measure's impact should it pass , such as requiring child-resistant packaging on marijuana products and putting strict limits on advertising.
Maine -- Recreational marijuana
Marijuana appears to be on stronger footing in nearby Maine. Polls conducted there earlier this year suggest the state's legalization measure currently enjoys upwards of 50 percent support.
Florida -- Medical marijuana
Florida voters narrowly rejected a constitutional amendment for a California-style medical marijuana market in 2014. While 58 percent of voters approved it, the measure failed to meet the 60-percent threshold necessary for a constitutional change.
This year's measure is similar to the failed 2014 initiative, but supporters hope that a more Democratic-leaning electorate in a presidential election year will tip the scales in their favor.
Florida's bill has garnered a number of high-profile endorsements from state and national political leaders, as well as groups like the NAACP, ACLU and some labor organizations. Most recent polls show support surpassing the 60 percent threshold needed for passage.
Arkansas -- Medical marijuana
Arkansas is also making a play to be the first southern state allowing medical marijuana. The effort recently received a boost when the state Democratic party put a call for medical marijuana into their party platform.
The measures are similar, and voters are free to vote for both. If both pass with a simple majority vote, the measure with the most support will be enacted. But there's also a danger of "splitting the ticket," and diluting medical marijuana support between two measures.
North Dakota -- Medical marijuana
In something of a surprise move, a medical marijuana measure recently qualified for the ballot in North Dakota. How this one will play out is anyone's guess. It appears the last polling on medical pot in the state was done in 2014, when 47 percent of voters approved of medical pot and 41 percent opposed it.
But North Dakota is a notoriously conservative state. Authorities there have already been warning about the alleged cost to implement the measure. But backers dispute the official cost estimates.
Montana -- Medical marijuana
For that reason, medical marijuana supporters have put a measure on the ballot that would roll back most of those restrictions and breathe some life back into Montana's medical marijuana regime.