Bill Montgomery was sworn in on Friday as one of seven justices on the state Supreme Court, but his personal bias against marijuana and record of going after medical marijuana patients as the Maricopa County Attorney have raised questions about his ability to rule impartially on future cases involving pot.

Montgomery's late father went to prison for selling marijuana. After his election nine years ago, the now-former county attorney went on a crusade against the plant — prosecuting medical marijuana patients for concentrates, calling a marijuana-using veteran "an enemy" whom he has "no respect for," and forcing marijuana users into an allegedly unconstitutional drug diversion program that he is currently being sued over.

No current marijuana cases are pending Arizona Supreme Court review. Even if that changed in the future, it's unlikely Montgomery's vote would mean much to the state's medical marijuana law, given the justices' past blowout rulings on related cases. In 2015, the state Supreme Court ruled 5-0 that prosecutors can't ban people on parole or probation from using medical marijuana. This past May, the court sided with Rodney Jones in a critical 7-0 decision that all marijuana concentrates are legal for medical marijuana patients under the Arizona Medical Marijuana Act (AMMA).

But Montgomery may have some influence over efforts to get recreational marijuana legalized next year.

"If there's a recreational marijuana initiative, and someone challenges it, Montgomery's vote would be an important one in keeping it off the ballot," said Paul Bender, professor of law and dean emeritus for the Sandra Day O'Connor College of Law. "Arizona gives an enormous amount of legislative power to the people, and the Legislature hates that, so they keep passing legislation to make it harder and harder to put things on the ballot."

In May, Arizona lawmakers made it even more difficult to get initiatives on the ballot by adding new requirements to the way signatures are collected. The new requirements add more hoops to jump through for those seeking to collect enough signatures to get an initiative on the ballot, and with that come more ways the signatures could be disqualified on a technicality.

Last year, the Arizona Supreme Court kicked a school-funding tax initiative off the ballot on a technicality. Supreme Court justices said the 100-word summary of the initiative presented to petition-signers was misleading.

A ballot measure to legalize recreational weed in Arizona failed to pass by a very slim margin back in 2016. It's likely the measure, backed by the Arizona Dispensaries Association, will have even more support this time around, as several more states have since legalized recreational marijuana.

Deciding whether or not to disqualify signatures on a ballot initiative is something that would be left up to the Arizona Supreme Court, and it seems fairly clear what way Montgomery would lean if given the chance to toss out a recreational marijuana bill.

"So with a recreational marijuana proposition, the Legislature has given — through statutes that it has passed — a lot of different ways to challenge propositions," said Bender. "The people who don't like the proposition will challenge it — virtually anybody has standing to challenge it — and the Arizona Supreme Court would have the last word on whether it stays on the ballot."

In 2010, the same year Montgomery was elected, Arizona voters passed the AMMA. But the will of the majority of Arizonans didn't seem to matter much to Montgomery, who continued to selectively prosecute medical marijuana patients and argued that despite AMMA, federal law still prohibited the county from allowing dispensaries. A state Court of Appeals judge rejected the county attorney's argument and said Montgomery had no legal basis for his claim.

But Montgomery still threatened medical marijuana patients with felony prosecution if they used extracts. In 2013, Montgomery threatened to prosecute a medical marijuana patient over one piece of THC-infused candy. The man was faced with the option of enrolling in a costly drug diversion program — the one Montgomery is being sued over — or serving up to three years and nine months in prison if convicted. Montgomery's office later dropped the charge, claiming that evidence had been destroyed.

Montgomery's hard stance on extracts led the parents of Zander Welton, who used CBD oil to help reduce the boy's frequent seizures, to sue Montgomery. Welton's parents won in 2014 when a county judge ruled against Montgomery, noting that the 2010 law plainly states that marijuana "and any mixture or preparation thereof" is legal for qualified users.

It was far from the only court-delivered blow to Montgomery's zealous prosecution of medical marijuana patients. Montgomery's prosecution of an Arizona State University student for possessing medical marijuana on campus led the state appeals court to find a 2012 law unconstitutional that had erased legal protections for medical marijuana holders on college campuses. In a 3-0 ruling, the court also tossed out the student's conviction.

In 2014, Montgomery got into a heated argument over marijuana with then-State Representative Ruben Gallego, who at the time was married to now-Phoenix Mayor Kate Gallego. When Ruben Gallego argued that it would be for the best to legalize marijuana, tax it, restrict it to adults 21 and over, and stop wasting resources criminalizing marijuana, Montgomery accused Gallego of being an "author of our societal suicide."

Then, in an unexpectedly personal turn moments before the debate ended, Montgomery snapped, "What is it with Harvard-trained politicians? ... Whether it's at law school or undergrad, [they have] bad ideas, can't follow laws, cheat on their wives, and come up with ridiculous ideas about marijuana."

Montgomery later said he wasn't accusing Gallego of infidelity.

Montgomery continued his crusade against a plant that is now fully legal in 11 states by taking it to the federal level in 2017, when he urged Congress not to pass an amendment that would stop the Department of Justice from spending money to enforce federal marijuana laws in states that have decriminalized it.

"Unfortunately, over the last eight years the marijuana industry has flourished nationally because the previous administration refused to enforce federal laws for marijuana offenses," Montgomery wrote in an op-ed published by The Hill.