Legislation to make pot legal will hit the House of Commons come spring, but the day when recreational marijuana becomes officially available to buy across the country could still be years away.

"I think one of the things we were struck by was how complex this transition actually is, and not only in terms of drafting legislation at the federal and provincial levels and putting in place all the infrastructure and training, but the psychological transition," former deputy prime minister Anne McLellan told CBC News Network's Power & Politics host Rosemary Barton.

"Going from something that has been prohibited for decades, to a world where it's a legalized product, sold in a regulated market — so the transition is going to be enormous," said McLellan, the chair of the federal government's cannabis task force.

The Department of Justice Canada will first have to embark on a widespread effort to change the Criminal Code and other related federal laws — that effort will kick off in the spring. But what that new law will look like and what kinds of challenges it will face as it moves through Parliament remain a mystery for now.

"This is just the task force report. I mean, obviously it should be influential, but the government could go in a different direction," said Eugene Oscapella, professor of law at the University of Ottawa.

That was certainly the case with the federal government's assisted-dying law. A Commons-Senate committee report tabled in advance of the assisted-dying law called for a much more permissive bill than the Liberal government introduced and passed.

Many are wondering if that could be the case again this time.

"They are going to introduce a bill. Who knows if it's going to buy the recommendations in this report. Please remember it's just recommendations. They might say, 'We like some, we don't like others.' A lot of them are in provincial jurisdiction anyway," said NDP MP Murray Rankin.

Oscapella said the federal government needs to start by sitting down and deciding exactly what parts of the legalization regime will fall under federal jurisdiction and what parts will be provincial.

'A huge practical problem'

Once the federal laws have been changed, Health Canada will have to design a regulatory system for weed, and all this has to happen before the provinces and municipalities figure out how to build a distribution and enforcement system.

"The capacity required to regulate the size of this new market — that is just a huge practical problem that is going to have to be overcome," said Neil Boyd, author of High Society, Legal and Illegal Drugs in Canada and professor of law in the School of Criminology at Simon Fraser University.

Boyd notes that the two main purposes of the move to end cannabis prohibition were to take the market away from organized crime and to keep the drug out of the hands of young people.

But if one province, for example, restricts the sale of weed to a mail order service, while a neighbouring province has a network of retail shops selling the drug, would people start moving it across borders, and if they did, would that be illegal? Or would it simply keep the illegal market open?

Who polices what?

Another concern Boyd raises is the costs of regulation. If regulation increases the price of marijuana well above the current black market price, would cutting out criminals still be possible?

Oscapella said it's one thing to make cannabis legal, but policing the regulations is a separate question. If someone is operating outside those new laws, are they committing a criminal offence, or a regulatory infraction?

If police have reason to believe a person is growing five plants instead of four, as recommended in the task force's report, would police have the same search and seizure powers they do now, or will those have to be changed as well?

These are questions Canada's police forces will want to have answered.

"There has to be a balance between accessibility and control because one objective that we have … is to address the organized crime, to make sure that we can take them away from the distribution and the point of sale as much as possible," said Mario Harel, president of the Canadian Association of Chiefs of Police.

"This balance of accessibility and being able to grow, or to be in possession, I think it's a delicate balance that the government has to address in their future bill," he added.

A long road ahead

Rankin said the parliamentary process, let alone the regulatory one, could take a long time to complete.

"You bring a bill in, it goes to committee, three readings … House and Senate. When will we have law? And when will they proclaim the law? It could be years from now," he said.

Liberal MP Bill Blair, parliamentary secretary to the minister of justice and the government's point man on pot legalization, concedes the effort will take time.

"The only precise time frame that we've committed to, is our minister of health has said she will bring legislation forward in the spring of 2017," Blair said.

"We know we've got a great deal of work to do to pass that legislation and even more work to put the regulatory framework and all of the infrastructure that will be necessary in order to do this right, and I will tell you; we are committed to taking the time to do it right."