The lawyer of one of the men who could have his citizenship revoked after being convicted of terrorism says there is no reason for his client to be punished twice for his crimes.

Last week, it was revealed that Zakaria Amara, a member of the so-called Toronto 18, had become the first Canadian in history to have his citizenship revoked.

Amara was found guilty of masterminding a plot to set off truck bombs in Toronto and outside a military base and sentenced to life in prison in 2010 with no chance of parole until 2016.

The government has also issued notices that it intends to revoke the citizenship of several other members of the terror group, including Saad Gaya, who is serving an 18-year sentence for his part in the plot.

Gaya’s lawyer, Lorne Waldman, has filed an application to the Federal Court challenging the constitutionality of the controversial law, which was passed last spring. He says his client is already paying the price for his crimes and shouldn’t have to be punished further.

“That is a Charter value that is enshrined in our legal system: you shouldn’t be punished twice,” Waldman told CTV’s Canada AM.

“...He was tried, he received a very severe sentence and he’s serving his sentence. That’s his punishment. In our legal system, people don’t get punished twice.”

The judge at Gaya’s sentencing found that with counselling, he could be a good candidate for rehabilitation, Waldman says, so there are no good grounds for revoking his citizenship.

“There is no question of security; there is no question of danger. This is just a double punishment,” he said.

But the federal government argues that citizens who commit “violent acts of disloyalty against Canada” such as terrorism, or “acts of war against Canada” should lose their right to be Canadian.

The legislation has led to outcry from the Liberals, NDP and others who worry the government extend citizenship revocation to people convicted of other crimes as well.

Waldman plans to argue that the government can’t revoke Gaya’s citizenship, as doing so would leave him stateless. Gaya, 28, was born in Montreal and is thus a Canadian citizen. But the government argues that because his parents were born in Pakistan, he also has Pakistani citizenship.

Waldman says that is not true, but the law has been drafted so that the onus is on Gaya to prove it.

“It’s contrary to our legal system to require a person to prove something; the onus has always been on the government. That’s one of the grounds under which we’re challenging the legality of the law,” he said.

Waldman says the Federal Court challenge will likely take months to work its way through the system. Both sides will file several motions in the matter and it could be a year before the court rules.

Then, there could be appeals all the way to the Supreme Court. “So it’s a long legal process,” he said.