Two Toronto lawyers argue that the Strengthening Canadian Citizenship Act , which could allow the government to revoke the citizenship of someone who holds dual citizenship, is unconstitutional.
Previously, a person could be stripped of Canadian citizenship for attaining it through false representations.
But the new law expands the list of those vulnerable to revocation to include people born in Canada but eligible to claim citizenship in another country — for instance, through their parents.
It also broadens the grounds for revocation to include several criminal offences including espionage, treason or terrorism.
After a day of arguments in court Thursday, Federal Court Judge Donald Rennie reserved his decision. But whichever way he rules, it's expected the case will be appealed all the way to the Supreme Court of Canada.
The challenge was launched by lawyers Paul Slansky, who represented the Constitutional Rights Centre, and Rocco Galati, who has been a thorn in the side of the Conservative government by successfully challenging the appointment of Marc Nadon to the Supreme Court and has also challenged the appointment of a Quebec Court of Appeal judge.
They argue that Parliament did not have the authority to legislate on the issue based on language about citizenship in the constitution.
The public should pay attention to the case, Slansky said, because even though the government will say these changes only deal with treason and terrorism offences, it could go further.
"If the court says they have authority to do this, what's to stop them from next week, next month, next year, from saying, 'Well, we're going to say you're no longer a citizen if you're convicted of any offence, or convicted of serious violent offences, or if you don't vote for the Conservative party?" he said outside court.
Government lawyer Greg George says the provisions are not yet being enforced, but "if and when" they are, they will be used against someone who has committed "some of the most serious, serious things that can be done against the state."
The judge wondered if the law creates two categories of Canadian citizens.
"We're saying citizens that hold dual citizenship can be removed to another country," Rennie said. "Citizens that don't, aren't going to be removed. And that creation of a distinction within the concept...has to be problematic."
No one would be rendered stateless under the law, George said.
"The only time a person would not be treated equally, so to speak, is if, again, they've committed some heinous crime, some very serious crime in regards to the state," he said. "It's not that these provisions will be used against a group of people, ethnic, religious, what-have-you. It's about individuals and their own choices."
The provisions will apply equally to natural-born and naturalized citizens, he said.
Galati said people born in Canada are citizens, "period," and once a citizen has been naturalized they have the same rights as someone who is natural born. Galati, who is himself a naturalized citizen, said unless there has been fraud in the naturalization process, the government does not have the legal authority to "yank back" that citizenship.