CNN  — 

Voters in Oklahoma will reject a ballot measure that would have legalized recreational marijuana in the state for adults ages 21 and older, CNN projects.

The vote in Oklahoma — where medical marijuana was legalized by voters in 2018 — reflects how the issue now transcends politics as well as geography, as Americans’ attitudes on the subject have moderated in recent years.

Recent polls show the majority of Americans now say they support legal marijuana. As attitudes shift, lawmakers show more willingness to make changes on the issue: five of the seven states to legalize recreational use in the last two years have done so legislatively.

Oklahoma would have become the latest state to exemplify how policies on the issue have changed — even in red states. Two-thirds of Americans were opposed to legalization two decades ago. That has now reversed.

Oklahoma would have been the fourth state with recreational marijuana that voted for former President Donald Trump in 2020.

Polling by Gallup shows that a majority of Republicans now support legalization, after decades of opposing the idea, reflecting a broader shift in the population.

Oklahoma is one of 37 states, plus Washington, D.C., that have a comprehensive medical cannabis program, according to the National Organization for the Reform of Marijuana Laws (NORML) and the National Conference of State Legislatures (NCSL).

But many provisions for medical and recreational use exist in gray areas. States have written a spectrum of laws, from fully legal markets collecting tax revenues to carve-outs for specific products.

That piecemeal legal network is the product of incremental advancements on a statewide level, as views on the drug have moderated over the past 27 years.

The legalization movement began in earnest after California voters approved medical marijuana in 1996. By 2012, after several other states adopted medical programs as well, Colorado and Washington voters were ready to cast their ballots for recreational legalization.

By 2022, enough forward momentum had built up that President Joe Biden ordered a review of whether marijuana should remain a Schedule I drug. That classification means marijuana has “no accepted medical use” from a federal viewpoint, like heroin.

But advocates remain skeptical of movement from the federal government after decades of inaction.

“If there was a tipping point that would influence the federal government or Congress to prioritize this issue, we’ve clearly passed whatever that tipping point may have been quite some time ago,” said Paul Armentano, deputy director of NORML.

Moving forward, however, more and more states could be legalizing through the work of their state legislatures, rather than with ballot initiatives, Armentano said. He noted that the number of states that can still make changes through the electorate is limited.

Of the 21 states and DC that have previously legalized recreational adult use, 15 have done so by ballot measure, while seven have been enacted by the state legislature.

Activists who supported Oklahoma’s legalization measure argued that recreational marijuana sales could bring in billions in tax revenue. Of the 21 states where recreational use is currently legal, 19 are collecting taxes on marijuana as of February, according to the Tax Policy Center.

Washington, DC was blocked from enacting taxes by Congress, and Virginia and Maryland are still in the process of getting their markets established.

“The way states do this can either be lightning fast or take a long time,” said Richard Auxier, a senior policy associate with the Tax Policy Center. The efficiency of states like Arizona and Missouri in getting their legal markets established shows that, “if you want to, you can go from zero to 60, real quick,” Auxier said.

In Oklahoma, which already has a robust market of medical retailers, the transition will likely be quick, said Bridget Hennessey, vice president of public affairs at WeedMaps, a tech startup that connects consumers with dispensaries. According to Leafly, another cannabis startup, there are at least 1,800 cannabis retailers currently operating in Oklahoma.

Ohio could be the next state where voters will take up the issue in November. With the addition of some other states that have introduced bills to legalize this year, by year’s end, nearly half of the nation’s states and D.C. could have a legal recreational drug market in defiance of federal laws.

“This is a political and cultural issue that defies all the rules we might’ve learned in civics class,” Armentano said.