Harkat, 44, was arrested almost 10 years ago in Ottawa on suspicion of being an al-Qaida sleeper agent. He denies any involvement in terrorism.
The federal government wants to deport Harkat under a national security certificate, a rarely used tool for removing non-citizens suspected of being terrorists or spies. He is one of three Muslim men whose certificate cases continue to grind through the courts.
Harkat lives at home with wife Sophie, but wears an electronic tracking bracelet on his ankle, must check in with authorities regularly and cannot leave town without permission.
"It's been a tremendous ordeal," said Norm Boxall, a lawyer for Harkat. "It's been a very long time."
No matter how the Supreme Court of Canada rules, Harkat's legal saga is far from over.
In April, the Federal Court of Appeal upheld the constitutionality of the security certificate system being used to deport him.
But the same appeal court ruled that summaries of some mid-1990s conversations be excluded from evidence against Harkat because the Canadian Security Intelligence Service destroyed the original recordings. It ordered the Federal Court to take another look at the certificate in this new light.
The ruling left both sides unhappy and each has asked for a hearing in the Supreme Court — an uncommon turn of events.
"It's certainly unusual, to say the least, that both parties would be seeking leave to appeal," Boxall said. "In this particular case, the decision of the Federal Court of Appeal clearly didn't satisfy either side."
The person named in a security certificate receives only a CSIS summary of the case against them, stripped of supporting information, which critics say makes the process patently unfair.
If the Supreme Court agrees to examine the security certificate system, the Conservative government will be backed into a familiar corner. The high court struck down the certificate regime in 2007, forcing the government to revamp the process to make it more fair to detainees.
The government reissued certificates against Harkat and others in early 2008 after a retooling that included the addition of special advocates — lawyers who serve as watchdogs and test federal evidence against the person facing deportation.
In the Federal Court of Appeal, Boxall unsuccessfully argued the presence of advocates did not ensure the constitutionality of the process. He said they were permitted to work only with the information presented to them and could not initiate their own investigations — even when open source material was at odds with the federal case.
Should the Supreme Court decide to hear the federal appeal, it would set the stage for renewed arguments over the written summaries of recorded conversations and the significance of destruction of the original tapes.
It is unclear how things with unfold, in a procedural sense, once the Supreme Court declares which — if any — appeal it will hear.
"I think right now what it is, is a lot of unknowns," Boxall said.