Crown lawyers argue that a fundamentalist Mormon leader should have relied on legal precedent instead of public statements from the provincial government for clarity on Canada's criminal polygamy laws.
Winston Blackmore, who was found guilty of practicing polygamy in July, has applied for relief from the Charter of Rights and Freedoms, arguing that his rights are being violated by criminal prosecution.
Blackmore has been practicing polygamy with 24 women between 1990 and 2014, according to his indictment. Jim Oler, a co-accused, was also found guilty of practicing polygamy with five women between 1993 and 2009.
Peter Wilson, a special prosecutor who approved the charges and is leading the case for the Crown, says that Blackmore was always at risk of prosecution even though the polygamy law under Section 293 of the Canadian Criminal Code has been constitutionally vague in the past.
Prosecutors have the discretion, based on the evidence, to approved criminal charges based on the evidence, Wilson said.
"We say that the applicant took a calculated risk when he engaged in activity that was prohibited by the Criminal Code," Wilson said. "That section applied, at all times, relevant to this case, and it still does and it applies to all citizens of Canada."
Blackmore's charter challenge alleges that he believed there would be no attempt to prosecute him for polygamy after an investigation in the early 1990s because officials within the Attorney General's office believed charging someone under Section 293 would be unconstitutional.
Blackmore's application relies on a 1992 news release declaring those opinions as validation that he would not be prosecuted for polygamy.
However, Wilson says that there needed to be a legal declaration from the courts, not a government official.
"It's clear, the Criminal Justice Branch cannot rule on Section 293," said Wilson. "It can opine on it and they did, (but) they can't rule on it. If the branch wants a ruling whether this section or that section is constitutional, they come here (Supreme Court) and ask for it."
Joe Doyle, who is serving as a friend of the court to ensure a fair trial, argued that Oler should not be prosecuted for the same reason as Blackmore, that he was led to believe through statements from the Attorney General, that he would not be prosecuted for polygamy.
"Given various comments from and on behalf of the Attorney General of B.C., his lack of concern regarding being prosecuted for polygamy is completely understandable and justifiable," said Doyle.
The constitutionality of Section 293 was legally addressed in 2011 in a reference case in B.C. Supreme Court, as Justice Robert Bauman ruled that it is not unconstitutional to charge someone with polygamy.
"The release of the polygamy reference was a sea change in the legal landscape," said Wilson. "Nothing could have been more significant to a charging decision, in the circumstances of this case, than that."
Both Blackmore and Oler were found guilty following their trial in April, however, a conviction hasn't been formally recorded until the charter challenge issue is settled.