In a new filing with the high court, the government argues its recently tabled bill doesn't overtake the high-profile issue of whether the Canadian Security Intelligence Service needs a warrant to seek allied help in spying on Canadians abroad.
It even draws parallels with the politically charged Airbus affair of the 1990s in making a case for greater certainty.
The government is urging the Supreme Court to hear the global spying case, saying a lower court ruling has left CSIS "in the dark" about when a judge's approval is needed to monitor suspected Canadian extremists in other countries.
But Gordon Cameron, an Ottawa lawyer appointed to probe the federal arguments, says the high court shouldn't bother with the case because the federal bill could make the central issue moot.
The legislation, introduced in late October, would explicitly allow CSIS to seek a warrant to investigate a security threat beyond Canada's borders — something the government flags as a pressing concern as a number of young Canadians travel to train and fight with terrorist groups abroad.
Cameron says in his written submission that if the high court decides to hear the case — against his advice — it should wait "a reasonable period" to gauge the bill's effect.
It is now up to the Supreme Court to decide whether to take on the case. A decision could be weeks away.
Federal lawyers say lower courts made "significant errors" in dealing with the delicate matters.
In a key 2013 ruling, Federal Court Justice Richard Mosley chastised CSIS over a request for warrants to track two Canadians with help from the Communications Security Establishment, Canada's electronic spy agency.
Mosley said CSIS breached its duty of candour by failing to disclose that CSE's foreign counterparts in the Five Eyes intelligence network — the United States, Britain, Australia and New Zealand — could be called upon to assist.
He also warned that CSIS and CSE were incurring the risk Canadian targets "may be detained or otherwise harmed" as a result of foreign agencies' use of the intercepted communications.
The Federal Court of Appeal upheld Mosley's judgment.
The appeal court declared that a warrant is required when CSIS — either directly or through the auspices of a foreign spy service — uses "intrusive" methods such as interception of telecommunications. It said such warrants could be issued when the interception "is lawful where it occurs."
The question of whether a warrant is required in such circumstances will remain "an important issue" even if the bill currently before Parliament becomes law, the government says.
The Supreme Court previously confirmed that Canada didn't need a warrant when it asked Swiss authorities to turn over banking records related to a criminal probe of alleged kickbacks in the sale of Airbus planes, the new federal filing says.
That suggests CSIS doesn't need one when asking its Five Eyes allies to spy overseas.
Still, the government adds, a high court ruling is needed to clear up the uncertainty.
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