The Conservatives abolished the registry for long guns in February 2011, fulfilling a five-year-old campaign promise after forming a majority government.
They also ordered that all data collected by the provinces be destroyed — a decision the Quebec government went to court to overturn.
A Quebec judge originally granted the province's request to preserve the data, calling it a constitutional infringement to destroy it.
But that decision was overturned by the Quebec Court of Appeal, which said there was no constitutional violation in the federal order to destroy the data.
The issue is politically charged because the Conservatives see mainly rural long-gun owners as a core constituency.
Earlier this month, Prime Minister Stephen Harper sparked controversy with his comment that guns provide "a certain level of security" to people who live far away from police stations.
NDP Leader Tom Mulcair, Quebec Premier Philippe Couillard and former Ontario attorney general Michael Bryant were quick to criticize Harper for the remark.
Jeremy Laurin, a spokesman for Public Safety Minister Steven Blaney, defended the government's decision to seek to have the gun registry data destroyed.
"It would be dangerous for our law enforcement to rely on outdated and obsolete information to conduct their operations," Laurin said in a statement.
He reiterated the government's oft-repeated position that the registry was wasteful and that the government "will always stand up for law-abiding hunters, farmers and sport shooters."
So, the Supreme Court will once again find itself ruling on a key area of the government's agenda.
The court has ruled against Conservative policy in a number of key areas, including rejecting the appointment of Quebec judge Marc Nadon to its ranks, rejecting Parliament's right to reform the Senate on its own and upholding the right of Vancouver's controversial Insite safe-injection facility to stay open when the government wanted to close it.
Friday's ruling deals with a narrow legal issue: the Quebec government isn't taking issue with Ottawa's jurisdiction to get rid of the long gun registry, only the provision to destroy the data.
Quebec is arguing that the registry was a joint effort between the provinces and the federal government, giving it the right to keep the data.
Under the registry, a lone federal registrar was responsible for issuing a certificate for each firearm. The registrar worked in conjunction with the various chief firearms officers in each province who would issue gun owners their possession licenses, as well as authorizations to carry and transport long guns.
They all had access to Canadian Firearms Information System, where all the information was stored and maintained by the RCMP.
The long-gun registry was borne of demands for stricter gun control in the wake of the massacre of 14 women at Montreal's Ecole Polytechnique in December 1989.
It's not the first time the gun registry has found itself the subject of debate at the high court.
After the Liberal government of the day established the registry in 1998, Alberta appealed to the Supreme Court saying Ottawa did not have the jurisdiction to impose such a measure on the province.
In 2000, the high court ruled unanimously that the federal government did in fact have to the right to enact a gun registry.
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