One of the federal Liberals' campaign promises in the recent election was to reintroduce a long-gun registry.

Of course they didn't call it a registry. Rather, Prime Minister Justin Trudeau proposed making gun sellers file records of every sale - purchaser's name and personal information, model of gun, serial number and so on.

That's a registry by another name, a registry via the backdoor. But it's still a registry.

There's nothing more persistent than a "progressive" with a bad idea. And trying to reduce crime by controlling the guns of law-abiding citizens is a bad idea that "progressives" have believed in for decades.

A registry is a bad idea not because it encroaches on an ancient right (which it does) or because it says symbolically that government, not the people, is the boss in our democracy (although it does that too).

It's a bad idea because it doesn't work.

And before governments tell free citizens what to do on any issue (not just guns), they had better be able to prove beyond a reasonable doubt that the restriction they want on freedoms will really, truly improve the situation.

But the reason progressives (liberals) cling to bad ideas so long is that they don't believe in independent proof. Their confidence in their own brilliance is so complete the very fact they believe in an idea is proof enough to them that it must be good. Don't waste their time with facts!

If criminals got report cards, one of the comments might be something like "Has trouble obeying rules and instructions."

It's the very nature of criminals to disobey laws. Indeed, it's impossible to become a criminal without breaking the law.

So it has always been laughable that progressives imagine criminals who are prepared to break much more serious laws against robbery, assault, drug trafficking and even murder could be persuaded by the passing of a bill to tell Ottawa and the police how many guns they have and where.

But in light of the recent horrific murders of two overnight convenience-store clerks in Edmonton there have been calls, especially online, for tougher gun laws. And, of course, the Progressive-in-Chief, Barack Obama, has called for stricter gun control in the States in the aftermath of the San Bernardino terrorist attack that killed 14 earlier this month.

Since Obama is a hero to Canada's new Liberal government, it likely won't be long before Trudeau et al begin suggesting anti-gun laws are a good way to confront the threat of terror here, too.

Consider what a futile exercise gun control would be, though, either in making all-night clerks safer or reducing the threat of terrorism here in Canada. The two suspects in Edmonton's ghastly, execution-style clerk killings late last week both had court orders against them prohibiting their possession of firearms.

A court order is a stronger former of gun control than a registry, in part because it is a total ban and in part because it is directed at a specific individual. Yet despite that, both of the adult suspects - Colton Steinhauer and Laylin Delorme - used restricted weapons in the alleged killing spree.

More than that, both men posted pictures of themselves on social media sites playing with machine guns. And machine guns aren't just restricted, they are outright prohibited. Still, both career criminals managed to get a hold of machine guns despite laws and court orders.

Former Ontario Premier Mike Harris used to have a great line in his stump speech: "How come every time a criminal commits a murder in downtown Toronto, Ottawa's first reaction is to restrict the guns of duck hunters?"

That's as true as it ever was.