What would municipal handgun bans accomplish and how would they work?

These questions persist after Liberal Leader Justin Trudeau pushed gun control to the fore of his campaign again this week.

The Liberals say they would empower local governments to "further restrict" or outright ban handguns as part of a bigger plan to curb crime. At the same time, they've rejected the idea of a countrywide prohibition on handguns and haven't explained how local bans would be more effective.

The commitment left A.J. Somerset, the London, Ont.-based author of Arms: The Culture and Credo of the Gun, wondering if the Liberals are "throwing a sop" to mayors and advocacy groups calling for action on gun crime.

Somerset argues that "there is no level on which it makes logical sense" to bypass a national handgun ban in favour of local ones.

That's because it's not clear that even a countrywide ban would seriously reduce gun crime, Somerset said — a position also taken by the Canadian Association of Chiefs of Police.

Certainly there could be some laudable outcomes, such as possibly increasing the street price of illegal handguns. But it wouldn't end the flow of weapons into Canada from the United States — a primary source of handguns used to commit crimes on this side of the border.

Take Toronto, for example. Police Chief Mark Saunders recently estimated that at least 80 per cent of illegal guns seized on the city's streets can be traced to sources in the U.S. Many of the remaining weapons are funnelled from other Canadian towns and cities.

That means that municipal bans would be even less effective at addressing the movement and sale of illegal weapons, Somerset said.

"You can easily move a handgun in and out of a city, regardless of a ban. And criminals are already doing that every day."

Cities in the United States have imposed handgun bans, only to have guns come in from outside.

Outlawing handguns in a city like Toronto would not safeguard against these realities, Somerset said.

Bill Blair, a Liberal candidate and minister of border security and organized crime reduction, suggested Tuesday that the party chose not to propose a national ban due to the high cost of a buyback program (there are more than 900,000 legally owned handguns in Canada) and because it would target law-abiding handgun owners.

The Liberal plan would allow individual municipalities to set parameters that work for them, Blair told reporters.

Bill Blair said this week that a national handgun buyback program would be an expensive proposition. (Adrian Wyld/The Canadian Press)

Legal uncertainty

But there are also questions about how local bans would work from a legal perspective. The Liberals have not explained how they would go about it.

Trudeau said Tuesday that the necessary "tools" would be made available to municipal governments, but it is not clear what that means.

There is the potential for some tricky legal wrangling, said Carissima Mathen, a professor and constitutional scholar at the University of Ottawa.

Prohibitions that come with the risk of punishment fall under criminal law, which is federal jurisdiction. But municipalities are creatures of the provinces. Therefore implementing local handgun bans would require at least some co-operation from all three levels of government, she said.

That could prove difficult in some cases. In Ontario, for example, Premier Doug Ford's Progressive Conservatives have rejected the idea of a handgun ban in Toronto, saying it would unfairly punish legal firearms owners.

Potential political hurdles aside, Mathen said it is certain that giving municipalities the option of outlawing handguns would, at the very least, require amendments to the federal Firearms Act and likely require changes to the Criminal Code as well.

"We would need a framework of actual statutes," she said. "I'd be very surprised if this policy was effected without some kind of law on the books."

CBC News sent a series of questions to Trudeau's campaign, asking for clarity on whether a re-elected Liberal government would pursue legislative action to help municipalities.

In an emailed response, a spokesperson for the Liberal campaign declined to directly address any of the questions.

Instead, the spokesperson reiterated Trudeau's boilerplate messaging, saying that a Liberal government would "work with provinces and territories" to make it possible for those communities which want to further restrict or ban handguns to do so.

"This is a priority commitment in the interests of public safety."