Oklahomans for Responsible Cannabis Action is facing a potential legal setback in its quest to get an adult-use cannabis legalization measure on the state’s 2022 ballot.

The group filed an initiative petition last month to get the issue before voters next year.

The proposal would allow adults 21 and older to grow, purchase, transport, receive, prepare and consume cannabis, and would levy a 15% tax on adult-use cannabis sales.

The measure would also allow those serving time for cannabis-related convictions to ask the court for resentencing or dismissal.

Paul Tay, a gubernatorial candidate and former Tulsa mayoral candidate who is currently incarcerated, has challenged the constitutionality of the proposal in court, according to a local KFOR report.

Tay alleges, among other points, that all signatures collected in Native American territory would be invalid due to a precedent set in McGirt v. Oklahoma. In that case, the U.S. Supreme Court ruled that much of the Eastern portion of Oklahoma remains Native American land, which means, under the Major Crimes Act, the prosecution of crimes in this area falls under the jurisdiction of the tribal courts and federal judiciary rather than Oklahoma’s courts.

Oklahomans for Responsible Cannabis Action Director Jed Green told the news outlet that Tay’s lawsuit is a “shotgun challenge” that goes after multiple points to see if any hold up in court. He added that his group believes it has “a really strong case.”

“The McGirt stuff is really kind of out of left field,” Green told KFOR, adding that Oklahomans for Responsible Cannabis Action is “confident” that it can overcome the legal challenge.

Both sides will present their cases on Dec. 14, KFOR reported, and the court will then decide if the petition can move forward.

If the court rules in its favor, Oklahomans for Responsible Cannabis Action must collect roughly 178,000 signatures to place its measure on Oklahoma’s ballot next year.