Utah's medical marijuana ballot initiative might be a First Amendment violation, claims a longtime marijuana opponent in a new lawsuit intended to remove the question from the state's November ballot.

On Thursday, Salt Lake City-area lawyer Walter J. Plumb III filed a lawsuit against Utah's Proposition 2, alleging that the measure—which would legalize medical marijuana for patients suffering from certain qualifying medical conditions as well as allow for the plant's cultivation and sale—would violate First Amendment guarantees to freedom of speech and free exercise of religion.

The sticking point for Plumb is a provision in Prop. 2 that would forbid landlords from discriminating against potential tenants solely because of their status as medical marijuana patients. This would force Plumb—a practicing Mormon and owner of a number of residential properties that he leases out—to associate with people and practices that run counter to his deeply held beliefs, something his lawsuit says is a violation of his religious liberties. The suit also claims that being forced to rent to medical marijuana patients amounts to "compelled speech."

"Members of all religions, including the Church of Jesus Christ of Latter Day Saints have constitutional rights to exercise their religious beliefs. This includes the right not to consort with, be around, or do business with people engaging in activities which their religion finds repugnant," the suit reads. "Any practicing member of the LDS faith would find this mandate deeply offensive and incredibly repulsive to their religious beliefs and their way of life."

Thursday's lawsuit against Prop. 2 is the second one for Plumb, who has a long history of anti-marijuana activism.

In the late 1990's, Plumb—a one-time law partner of Sen. Orrin Hatch (R–Utah)—mailed out an unsolicited, 60-page pamphlet to some 7,000 Salt Lake residents, warning of the dangers of cannabis consumption.

"I think it's the best work on marijuana that's ever been out. I think this is specific and gives parents help and direction," Plumb told the Deseret News in 1998. He was speaking of his own pamphlet, which included a glossary of marijuana-related terms, as well as notes on which of these terms were used exclusively by blacks and Hispanics.

Whatever the quality of that work, Plumb's lawsuit is unlikely to go anywhere, says Connor Boyack of Utah's Libertas Institute, a libertarian think tank and one of the organizations advocating for a 'yes' vote on Prop. 2.

In addition to the First Amendment claims in Thursday's suit, which he describes as "a huge stretch," Boyack says the lawsuit lacks "ripeness"—a requirement that litigation not be based on hypothetical future harms.

"Even if their claim were to have merit in the eyes of a judge, they can't do anything until after the initiative passes into law," Boyack says.

An opponent of anti-discrimination laws on property rights grounds, Boyack nevertheless says that the religious claims in Plumb's lawsuit also miss the mark. "The contention in the lawsuit that our religion considers medical marijuana users to be repugnant is not only false, it's abjectly stupid. It has no basis in truth," says Boyack, himself a practicing Mormon, who notes that the church's health code is silent on the use of marijuana as a medicine, although it does include prohibitions on "illegal drugs," as well as perfectly legal substances like coffee and alcohol.

Boyack says Thursday's lawsuit is the latest in a bag of dirty tricks used by marijuana opponents to keep the popular Prop. 2 measure away from voters.

Back in May, after Prop. 2 supporters had collected enough signatures to put their initiative up for a vote in November, a coalition of opponents—including the Utah Medical Association—paid canvassers $25 an hour trying to convince enough people to remove their names from the petition to get it booted off the ballot. That tactic failed, as did a previous lawsuit which was filed and then quickly retracted over the same ripeness issue.

Currently, Prop. 2 is polling at two-thirds support. Provided Plumb's lawsuit fails to get the initiative kicked off the ballot, it will likely coast to victory in November, making conservative Utah the 31st state to legalize marijuana for medical purposes.