Horne says it's illegal under Arizona's medical marijuana law to exchange pot for money, even if it is between approved patients.
The law, narrowly passed by state voters in November, is in disarray after Horne sued the federal government in May to find out whether state employees regulating the program would face prosecution.
That action essentially put the law on hold, although the state still is handing out medical marijuana cards to patients with qualifying diseases for fees of $150 each.
The Arizona Department of Health Services was set to accept the applications of would-be pot shops starting June 1, but Horne's suit stopped that. No marijuana dispensaries have been approved to operate in the state and won't be until the federal court action is decided, which could take months.
Horne told The Associated Press that he could order the cannabis club operators arrested, but he decided to give them the benefit of the doubt because it's a new law that's difficult to understand.
The clubs will be allowed to continue to operate until the Phoenix judge issues an opinion, possibly within the next few weeks.
"Once we get a civil judgment and it becomes clear to everyone, then they would be subject to arrest," Horne said.
A spokesman for one of the clubs said they are excited to finally have a judge to weigh in on the issue.
"We are adamant in our position that this is absolutely legal," said Allan Sobol, a spokesman for The 2811 club in Phoenix. "And we'll prove that in court."
The club's roughly 500 members, who all have medical marijuana cards, exchange pot among themselves without paying each other, he said.
Club members pay $75 to use the facilities for the day and have access to various classes, such as those that teach patients how to make marijuana food products, he said.
"They have to pay a club fee to get in the door, but they're not paying for the marijuana," Sobol said. "If that judge tells us we're wrong, we'll close up that day, but I don't believe that's going to happen."
Sobol said Horne and other state officials are effectively stopping Arizona's medical marijuana law from being carried out, while Horne said the clubs simply found a way to skirt the law.
The department so far has approved more than 8,600 patients to have and use medical marijuana. Of those, more than 6,900 have been approved to grow up to 12 plants each.