OTTAWA -- It has taken more than 40 years but the government of Canada is finally formally committing to legalizing marijuana.

Gov. Gen. David Johnston delivered the governing priorities of Justin Trudeau's Liberals in the speech from the throne Friday, including a pledge to "legalize, regulate and restrict access to marijuana."

The Liberals promised to legalize pot more than a year ago, prompting a months-long barrage of Conservative attack ads in multiple languages that asserted the move would make marijuana readily available to children through sales at corner stores.

The scare tactics failed to avert a Liberal majority government when Canadians went to the polls on Oct. 19.

Yet amid a flood of priorities from the highly activist Liberals, no one seemed absolutely certain marijuana legalization would make the cut.

But there it was Friday, in a section of the throne speech headlined "Security and Opportunity" -- some 43 years after a federal inquiry headed by Gerald Le Dain recommended in 1972 that Canada stop prosecuting people for simple possession and cultivation of cannabis.

"The actual perception of harm of cannabis is now so different from that which the law would suggest, that any change in the law could only be recognized as a belated recognition of the facts," the commission reported -- four decades ago.

Donald MacPherson, the director of the Canadian Drug Policy Coalition at Simon Fraser University's Centre for Applied Research in Mental Health and Addictions, called Friday's throne speech "a groundbreaking day."

Decriminalization or legalization is being discussed "in virtually every country where cannabis is being used," MacPherson said in an interview from Kelowna, B.C., adding Canada's policy move has been called for by public health practitioners and is long overdue.

He said pot usage rates by Canadian youth are "through the roof" and a policy of smart regulation to restrict access is worth a try.

"We can't do worse than we're doing now."

Lawyer Alan Young, a longtime advocate of legalizing marijuana, said the most compelling argument against legalization was the potentially harsh reaction by Canada's biggest trading partner, the United States, but American public opinion and policy have moved so far in the past decade that caution is no longer needed.

Canada's pot prohibition has been "imposing an enormous burden on a criminal justice system that is already over-extended," said the Osgoode Hall law professor.

Young has been advocating a policy shift for more than 30 years and says he's been let down by governments before, but believes this time the law will change, having discussed the matter directly with Trudeau when the Liberals were first formulating their policy.

"But I don't want to paint Justin Trudeau as a hero, because he's come in at an easy point when the U.S. has backed off" on its war on drugs, said Young.

Pot activist Jody Emery called the throne speech a "fantastic" acknowledgment of the failure of prohibition.

But she said the heavy regulatory approach that seems to be emphasized in the Liberal approach is unnecessary and counterproductive.

She and her husband Marc Emery, Canada's self-styled Prince of Pot, will be calling on Trudeau to announce a moratorium on marijuana arrests while they develop the details of their legalized pot policy.