While Canadian officials hailed the ruling as a strong message, advocates of the practice challenged Bauman's conclusion that it is inherently harmful to the families involved and to society at large.
"If [polygamous families] were to live it openly, without the threat of law, many of the people saying there's inherent problems would find that's not the case," said Marlyne Hammon, a member of the Arizona-based Centennial Park Action Committee.
Utah Attorney General Mark Shurtleff has been watching the Canadian case develop alongside a challenge to this state's bigamy law filed in U.S. District Court by the polygamous family of Cody Brown stars of the reality show "Sister Wives."
The Brown lawsuit differs from the Canadian case in that it relies on a legal right to privacy instead of a religious freedom argument, which was discarded by the U.S. Supreme Court in a bigamy case more than 100 years ago. However, both cases ask whether polygamy, when practiced by consenting adults, is truly harmful to society.
"It's the same analysis our courts will go through if the Cody Brown case gets to that point," said Shurtleff, who applauded Bauman's conclusions. "I think it's how the U.S. Supreme Court will rule if it ever gets to the Supreme Court here."
The Canadian case stemmed from an investigation into two polygamous factions in a community of about 1,000 known as Bountiful, located just outside of Creston, British Columbia. Members follow the practices of the Fundamentalist Church of Jesus Christ of Latter Day Saints, historically based in Hildale, Utah, and Colorado City, Ariz.
Charges of practicing polygamy filed against then-rival leaders James Oler and Winston Blackmore were thrown out on the basis of religious freedom by a court in 2009, prompting the Attorney General of British Columbia to ask the province's Supreme Court to decide once and for all if the law banning polygamy should stay on the books.
Prosecutors argued the law should stay because polygamy is harmful, and over several months of hearings introduced evidence uncovered by authorities in Texas during a massive 2008 raid on a remote FLDS ranch showing evidence of underage marriage, including unions of 12 and 13-year-old girls to FLDS leader Warren Jeffs. Some of that evidence would later be used in Jeffs' trial on two counts of sexual assault of a child in Texas, where he was convicted and sentenced to life in prison.
Attorneys seeking to strike down the law argued it violates the country's guarantee of religious freedom, and is overly broad; the Canadian Polyamory Advocacy Association argued the law could also be used to prosecute their members for participating in consensual intimate relationships among multiple adults.
Bauman agreed with prosecutors, pointing to global research that connects polygamy to lower life expectancy, education, marriage ages and legal protections for women and girls. He also cited higher rates of sex trafficking, domestic violence, and maternal mortality.
Hammon argued the evidence is skewed because many polygamous families are forced into underground lifestyles.
"Where you have to isolate people, it's a breeding ground for people to go to other criminal acts," she said.
Carolyn Jessop, who chronicled her abusive plural marriage in the FLDS of the bestselling book "Escape," testified that a repeal of the ban would allow polygamous societies to be more open to law enforcement and report other crimes.
Bauman also cited evidence that polygamy "generates a class of largely poor, unmarried men who are statistically predisposed to violence and other anti-social behaviour."
Hammon argues it is unreasonable to think the numbers of unmarried men would suddenly escalate to the point of an underclass if polygamy were legal.
"You can guarantee not everyone is going to jump on board," she said. "I think things balance out. How many men [already] choose not to marry? How many gays, how many lesbians?"
George Macintosh, a lawyer appointed to oppose the anti-polygamy law at the Canadian hearings, said he would likely launch an appeal. The case is expected to wind up in Canada's Supreme Court.
Blackmore, who is alleged to have 19 wives, has long claimed religious persecution and said Wednesday he would continue to fight.
"I certainly don't plan on dropping my faith and running away," he said. "The government has tried to do everything they could in the last 20 years to ruin our lifestyle. How can the Supreme Court of Canada uphold swinging and swapping clubs? A plural relationship doesn't kill anybody. The judge: he's wrong."
Bauman's ruling could open the door to additional prosecutions in Canada. British Columbia Attorney General Shirley Bond said Wednesday she had not yet decided whether to refile charges against Oler and Blackmore or to pursue additional cases.
"We're going to take some time [and] make sure we understand this ruling," Bond said.
As part of the ruling, Bauman noted that the law should not be used to prosecute children ages 12 to 17 in polygamous marriages.
Reporter Lindsay Whitehurst and the Associated Press contributed to this report.
Wednesday's ruling could lead to additional prosecutions in British Columbia, but will likely be appealed to Canada's Supreme Court.