Nine states will be voting on some form of marijuana legalization come Tuesday, Nov. 8. Pictured: Marijuana plants grow in full sun in Pueblo County on Sept. 3, 2016. Pueblo County is one of the few places in Colorado that currently allows for outdoor commercial cannabis cultivation, such as Los Sueños Farms LLC. (Vince Chandler, The Denver Post).

Cannabis at the ballot box: Is the push for U.S. marijuana legalization reaching critical mass?

It’s a pivotal moment for marijuana in the United States.

Come Tuesday, voters in five states — Arizona, California, Massachusetts, Maine and Nevada — will decide whether to legalize the recreational use of cannabis; and residents in four other states — Arkansas, Florida, Montana and North Dakota — will weigh medical marijuana measures.

“It’s hard to imagine that all nine ballot initiatives fail,” said John Hudak, a marijuana policy expert and author.

And while a clean sweep also appears unlikely, the more states adopting marijuana laws — especially the economic force of the populous California — could push the needle a little further in the direction of broad-scale federal legalization, said Hudak, who serves as a senior fellow in governance studies for the nonpartisan Brookings Institution.

“The size of the California market coming online and being legal is going to be fairly significant,” he said. “The economic implications are tremendous, and certainly there will be political implications.”

If Proposition 64 passes, members of Congress also may very well look at the state and chalk it up to California being California, and that the state is regulating what was already happening in a gray market capacity, he said.

“I think on its own and in and of itself, California is not that gamechanger,” he said.

However, the ease at which the California legal market is formed and developed could carry some greater weight, he added.

A move by California to legalize the recreational use of marijuana has been considered by some as a potential “watershed moment” for the cannabis industry.

If Proposition 64 passes and is implemented by 2018, California could have a $6.5 billion marijuana market in 2020 — accounting for nearly a third of the estimated 2020 sales for the entire U.S. cannabis industry, according to market research reports from the Arcview Group and New Frontier Data.

As it stands now, the industry is projected to tally $7.4 billion in revenue this year. Half of the U.S. states have medical marijuana laws in place and several others have adopted the use of low-THC cannabis oil for limited medical purposes. On the recreational side, Colorado, the first to allow legal sales of adult-use cannabis, now has company in Washington, Oregon, Alaska and Washington, D.C.

Public support of marijuana legalization also is at its highest-ever levels, according to recent polls by Pew Research Center and Gallup. The bulk of the support is coming from the younger generations, Pew’s survey showed.

Some marijuana measures up for vote have been trending favorably; but others, such as the medical marijuana proposal in Arkansas, are likely to come down to the wire. The measures have been heavily contested.

And even if some or all of the marijuana measures are successful on Tuesday, Hudak said that he’s “not convinced we’re at that critical mass.”

“We have had very little federal-level medical marijuana reform,” he said.

Earlier this year, the U.S. Drug Enforcement Administration stood pat on keeping marijuana a Schedule I substance on the Controlled Substances Act — in the same category as heroin and LSD — while easing some restrictions for research on the cannabis plant.

Other policy experts say the success of the 2016 marijuana measures could potentially spur action at the nation’s highest office.

“If you’re sitting in the White House, you have to say, ‘Gosh, that might be enough,’ ” said Mark Kleiman, professor of public policy at New York University’s Marron Institute of Urban Management.

Federal legalization likely won’t happen with a flip of the switch, but the increased adoption of these laws could spur increased dialogue on banking- and tax-related issues that have dogged the industry, he said.

The two leading presidential candidates have both said they support marijuana legalization from a states’ rights perspective. Democratic nominee Hillary Clinton has committed to rescheduling marijuana to Schedule II, and Republican nominee Donald Trump appears to be hands-off on this topic, but some of the rhetoric around substance abuse “would lead you to believe he’s certainly not going to be a reformer,” Hudak said.

The biggest concern for the marijuana industry would be the possible appointment of Chris Christie as U.S. Attorney General, Hudak said, referencing the New Jersey governor who has been a staunch critic of legalization.

“I think there’s a much bigger risk of federal intervention,” Hudak said.

Marijuana on the ballot in 2016

Recreational measures

ARIZONA: Proposition 205 would allow adults 21 and older to carry up to an ounce, grow up to six plants and consume marijuana in non-public spaces. Retail marijuana sales would have a 15 percent tax imposed. Retail shops would not open until at least 2018.

CALIFORNIA: The passage of Proposition 64, a.k.a. the Adult Use of Marijuana Act, would allow adults 21 and older to possess up to an ounce of cannabis, purchase dried flower and cannabis products from licensed retailers and grow up to six plants for personal use. Among the provisions of the 62-page initiative are an allowance for local government regulations, bans and taxes; proposed state tax of 15 percent on retail sales and separate taxes for cultivation; and restrictions on where cannabis can be consumed.

MAINE: With Question 1, voters will decide whether to allow marijuana possession and sales for adults 21 and older, who could also grow up to six plants. The proposal includes a 10 percent retail sales tax. The initiative has prohibitions on places of consumption, including restricting use to a private residence, and it allows municipalities to regulate the number of retail stores or ban them entirely.

MASSACHUSETTS: Under the Question 4 measure, adults 21 and older can possess up to an ounce of pot, keep up to 10 ounces of marijuana at home and grow up to six plants. Marijuana sold in licensed shops would be subject to an excise tax of 3.75 percent in addition to Massachusetts’ 6.25 percent state sales tax. The initiative allows for the creation of a 15-member cannabis advisory board to study and make recommendations on regulations and marijuana products.

NEVADA: The Regulation and Taxation of Marijuana Act, or Question 2, would make it legal for adults age 21 and older to buy marijuana for recreational use, possess up to an ounce and grow up to six plants at home — if that residence is more than 25 miles away from a licensed dispensary. The initiative includes some limitations on the number of retail outlets in a specific county — the populous Clark County, home to Las Vegas, can have up to 80 shops, while every other county under 55,000 people can have no more than two recreational stores. Wholesale marijuana would be subject to a 15 percent excise tax. Cannabis consumption would be restricted to private premises, which could include a retail marijuana store.

Medical measures

ARKANSAS: If approved by voters, the Arkansas Medical Marijuana Amendment (Issue 6), is a proposed constitutional amendment that would allow an independent commission to award licenses for up to eight grow facilities and up to 40 for-profit dispensaries statewide. Home growing is not allowed. There were initially two medical marijuana measures on the ballot, but one failed a legal challenge that went to the state’s highest court and its votes will not be counted.

FLORIDA: Under the Amendment 2 proposal, the state Department of Health would register and regulate dispensaries as well as issue ID cards to patients and caregivers. Individuals with medical conditions such as HIV/AIDS, epilepsy, multiple sclerosis, PTSD and Crohn’s would have to receive approval from a licensed Florida physician to be eligible for medical marijuana. The amendment requires parental consent for minors. A successful constitutional amendment in Florida requires at least 60 percent approval to pass. Two years ago, a medical marijuana measure also on the ballot as Amendment 2 fell 2.4 percent shy of that threshold.

MONTANA: The state program, approved by voters in 2004, has been in flux this year amid a court battle. In February, the Montana Supreme Court upheld 2011 state laws limiting medical marijuana providers to three patients apiece; the law went into effect Aug. 31. Initiative 182 was filed as a means of expanding legal access to medical marijuana. The proposed initiative would repeal the three-patient limit and other requirements such as unannounced inspections and required reviews for physicians who provide certifications. The qualifying conditions under this initiative would include chronic pain and PTSD.

NORTH DAKOTA: Initiated Statutory Measure No. 5, a.k.a. The North Dakota Compassionate Care Act, would allow for the possession of up to 3 ounces of marijuana for qualifying conditions such as AIDS, cancer, epilepsy and glaucoma. The proposal allows for people who live more than 40 miles from a licensed dispensary to grow up to eight plants.

For more detailed information on the ballot measures and the latest marijuana news out of each state, read The Cannabist’s guide to marijuana on the 2016 ballot.