LANSING, Mich. — Backers of broad marijuana legalization are looking to break through a geographic barrier in November and get their first foothold in the Midwest after a string of election victories in Northeastern and Western states.

Michigan and North Dakota, where voters previously authorized medical marijuana, will decide if the drug should be legal for any adult 21 and older. They would become the 10th and 11th states to legalize so-called recreational marijuana since 2012, lightning speed in political terms.

Meantime, Missouri and Utah will weigh medical marijuana, which is permitted in 31 states after voters in conservative Oklahoma approved such use in June. Even if Utah’s initiative is defeated, a compromise reached last week between advocates and opponents including the Mormon church would have the Legislature legalize medical marijuana.

“We’ve kind of reached a critical mass of acceptance,” said Rebecca Haffajee, a University of Michigan assistant professor of health management and policy. She said the country may be at a “breaking point” where change is inevitable at the federal level because so many states are in conflict with U.S. policy that treats marijuana as a controlled substance like heroin.

“Generally, people either find a therapeutic benefit or enjoy the substance and want to do so without the fear of being a criminal for using it,” Haffajee said.

Two years ago, voters in California approved a ballot measure creating the world’s largest legal marijuana market. Oregon, Washington, Alaska, Colorado and Nevada are other Western states with legal marijuana for medical and personal uses. On the other side of the country, Massachusetts, Maine, Vermont and Washington, D.C., have legalized recreational marijuana, and every other Northeastern state has approved medical marijuana.

In Michigan, surveys show the public’s receptiveness to marijuana legalization tracks similarly with nationwide polling that finds about 60 percent support, according to Gallup and the Pew Research Center.

The Washington-based Marijuana Policy Project was the driving force behind successful legalization initiatives in other states and has given at least $444,000 for the Michigan ballot drive.

“The electorate is recognizing that prohibition doesn’t work. There’s also a growing societal acceptance of marijuana use on a personal level,” said Matthew Schweich, the project’s deputy director.

“Our culture has already legalized marijuana. Now it’s a question of, ‘How quickly will the laws catch up?’?” added Schweich, also the campaign director for the Michigan legalization effort, known as the Coalition to Regulate Marijuana Like Alcohol.

Midwest voters have considered recreational legalization just once before, in 2015, when Ohio overwhelmingly rejected it. Supporters said the result was more back lash against allowing only certain private investors to control growing facilities than opposition to marijuana.

Proponents of Michigan’s measure say it would align with a new, strong regulatory system for medical marijuana businesses and add roughly $130 million annually in tax revenue, specifically for road repairs, schools and municipalities. Military veterans and retired police officers are among those backing legalization in online ads that were launched Tuesday.

Critics say the Michigan proposal is out of step and cite provisions allowing a possession limit of 2.5 ounces that is higher than many other states and a 16 percent tax rate that is lower. Opponents include chambers of commerce and law enforcement groups along with doctors, the Catholic Church and organizations fighting substance abuse.

Randy Richardville, a former Republican legislative leader and spokesman for the opposition group Healthy and Productive Michigan, said adults — even those without serious health problems — already can easily obtain pot under the state’s lax medical marijuana law. The ballot proposal, he said, would lead to a more “stoned” workforce, car crashes and crimes, and increased health risks for teens.

“This has nothing to do with a citizens’ initiative with a whole bunch of people out there that said they would like to smoke marijuana recreationally and responsibly,” Richardville said.

Dr. Donald Condit, an orthopedic surgeon in Grand Rapids who is helping lead physicians’ opposition, said few doctors see a problem with, for example, terminal cancer patients using marijuana to ease their pain.

But people should think harder about full legalization because marijuana is becoming “very, very potent” and “this stuff could hit the teenage developing brain like a ton of bricks,” he said.

Backers counter that teens’ use of marijuana has not increased in states that already have approved recreational use and point to the drug’s other benefits, like as a safer substitute for painkillers amid the deadly opioid epidemic.

“It’ll take the scourge of the old days when drug dealers sold heroin and crack and methamphetamines and marijuana — it was all lumped together” said Stu Carter, who owns Utopia Gardens, a medical marijuana shop in Detroit. “Now we can pull that away from that illegal drug world and make it much safer for the consumer.”

In North Dakota, legalization faces an uphill battle. No significant outside supporters have financed the effort, which comes as the state still is setting up a medical marijuana system voters approved by a wide margin two years ago.

The medical marijuana campaign in predominantly Mormon Utah, which has received $293,000 from the Marijuana Policy Project, was jolted this month when Gov. Gary Herbert said he will call lawmakers into a special post-election session to pass a compromise deal into law regardless of how the public vote goes.

Medical marijuana also is on the ballot in Missouri and while the concept has significant support, voters may be confused by its ballot presentation.

Supporters gathered enough signatures to place three initiatives before voters. Two would change the state constitution; the third would amend state law. If all three pass, constitutional amendments take precedence over state law, and whichever amendment receives the most votes would overrule the other.

An organizer of one amendment, physician and attorney Brad Bradshaw, said it is unclear if having three initiatives could split supporters so much that some or all of the proposals fail.