MEXICAN WATER, Ariz. — For Navajo spiritual leader Steven Benally, saving a Native American religion from extinction means preserving those diminishing lands where hallucinogenic peyote grows wild.

“It’s a small but important step toward realizing a prophecy,” he said.

Preservation also means battling activists in the Bay Area and other cities who want to legalize consumption of the psychedelic cactus.

“To these outsiders, we say, ‘Leave peyote alone. Please,’” Benally, 61, said. “Is that too much to ask?”

Under federal law, only members of the Native American Church are authorized to ingest peyote. That could change, however. Cities across the nation are considering decriminalizing an array of mind-bending plants and fungi known as the “Big 5” — magic mushrooms, iboga, ayahuasca, huachuma and peyote.

The movement is led by the nonprofit Decriminalize Nature, whose mission statement envisions happier and healthier people as a result of legalization.

Decriminalize Nature’s mission statement suggests that peyote and other natural hallucinogens should be accessible to everyone, not just Native Americans, because they can induce inspirational and enlightening experiences.

But some Native Americans are deeply offended by the inclusion of peyote in the surprisingly popular decriminalization movement and worry about the impact it could have on diminishing populations of the ground-hugging cactus.

Now, in a racially tinged clash that has come to be known as “the peyote crisis,” leaders of decriminalization efforts are learning a hard lesson in the complexity and volatility of Native American law and policy — both of which can change as quickly as the weather here in the backcountry of the Navajo Nation.

As the morning sun crested copper-hued mesas in the Four Corners region of Arizona, Colorado, Utah and New Mexico recently, Benally said he was saddened to see peyote swept up in a national psychedelic trend.

Benally helps lead a nonprofit created, in part, to manage a newly purchased 605-acre ranch laden with the spineless, blue-green succulent that pops out of the ground like biscuits in the Rio Grande Valley and northern Mexico, the only place on Earth it grows wild. Access to peyote should remain restricted to the estimated 400,000 members of the Native American Church, he says.

“Peyote is sacred medicine crucial to our religious identity and the survival of our community,” he said. “The spiritual healing power it offers is only attainable through Native American protocol. It is intended to nourish the soul in troubled times and inspire our children to become responsible men and women.”

Holding up a dried peyote button about the size of a quarter, Benally smiled and added, “Under federal law, only members of the Native American church can possess or use this sacred medicine.”

“It is one of the few federal laws on our side, and we want to hold on to it.”

But not all Native American leaders agree with Benally.

“Maybe decriminalization of peyote for everyone is the best thing,” said William Voelker, a Comanche and director of the nonprofit Sia , a group dedicated to preserving the traditional spiritual importance of eagle feathers in Native American culture and traditions. “It wouldn’t be very humble of us to claim exclusive ownership to peyote and prevent others from using it. It wasn’t just given to us.”

In addition to inducing feelings that are hard to distinguish from the sensations that mystics have interpreted as divine dialogue, some scientific research suggests that the psychedelics may prove useful in treating mental health issues such as depression, PTSD, anxiety and addiction. The therapeutic benefits of peyote and other natural mind-bending plants should be available to everyone, they say.

But this argument has been less than persuasive for those Native Americans who view peyote as a divine gift — a sacrament consumed to focus worshipers’ prayers to the Creator. Their legal right to have access to it and use it is the result of costly court battles and painful cultural struggles with the United States government, they say.

“Trying to tear Native Americans away from a plant that is intricately entwined with their culture and spiritual beliefs is simplistic and short-sighted,” said Miriam Volat, a soil scientist and co-director of the RiverStyx Foundation. “Instead of saying, ‘You owe us this plant,’ the decriminalization movement should be saying, ‘We’d like to help you take care of your sacred medicine.’”

The controversy emerged after the Oakland City Council unanimously approved a resolution to make the use, possession and cultivation of plants and fungi that contain naturally occurring psychoactive compounds a very low priority for law enforcement.

The city action was taken without input from leaders of the National Council of Native American Churches and the Indigenous Peyote Conservation Initiative. They responded with a formal statement asking that their groups not be referenced as supporters of the movement without their formal permission. It also said, “We believe that the respectful course is to NOT include the word ‘peyote’ in local resolutions or initiatives to put before governing bodies.”

In an interview, Carlos Plazola, a real estate developer and co-founder of Decriminalize Nature Oakland, which wrote that city’s ordinance and successfully lobbied for its passage, said his group agreed to remove the word “peyote” from its website and is now actively encouraging cities to take it out of proposed legislation.

Dawn Davis, 43, an expert in peyote conservation and a member of the Shoshone-Bannock tribes of Fort Hall, Idaho, worries that decriminalization efforts will renew the kind of fascination with psychedelic experiences that moved a generation of seekers to buy peyote from black market sources in the 1960s.

“To us, peyote is an ancestor and a living relative,” she said. “Cultivation of peyote outside of the ancient terrain it shares with indigenous people is a step toward hybridization and commercialization.”