Even some of the most passionate advocates of an end to pot prohibition acknowledge that legalization is a much more complicated public policy than the "just say no" criminalization model that critics say is such an abject failure.
From Canada's signature on international drug conventions to the logistics of local marijuana production, distribution and taxation, a host of crucial policy decisions will face any government that attempts legalization.
"You have to think harder about how to regulate it," says Eugene Oscapella, who teaches drug policy in the criminology department at the University of Ottawa.
"With criminalizing, we just ban it so we don't have to think too much — but it doesn't work and it causes tremendous problems. To actually develop an intelligent policy requires a lot more work."
Interim Liberal Leader Bob Rae alluded to those looming headaches at last weekend's party policy convention, where 77 per cent of voting delegates endorsed the pot legalization model.
"It's now up to us to take that resolution and see exactly what it will mean in terms of policy," said Rae, "because there are some practical questions we have to look at."
Many of those practicalities are hinted at in the lengthy Liberal resolution.
It commits the party to "legalize marijuana and ensure the regulation and taxation of its production, distribution, and use, while enacting strict penalties for illegal trafficking, illegal importation and exportation, and impaired driving."
The resolution goes on to propose increased youth drug education (already a government policy), an amnesty and record clearance for all previous convictions of simple possession, and federal-provincial negotiations on regulatory control "while respecting ... particular regional concerns and practices."
Mark Haden, an academic at the University of British Columbia and author on drug policy issues, has developed spreadsheets that lay out various options for distribution models.
"The commercialization model versus the public health model is really the first decision, and then all things flow from that," said Haden.
"I think the public fear is we're going to give it to the commercial companies and they're going to take it and run with it. And that isn't true. Well, it could be true, but it's a truth I strongly advocate against."
Among the questions policy-makers must ask:
— What sort of branding, if any, and packaging would be permitted?
— What would the age limit be for consumption?
— Who would be permitted to grow marijuana, and in what quantities? Would only licensed growers be allowed to produce pot?
— What would be the distribution point, public or private enterprise?
— Would there be volume limits on individual purchases, unlike alcohol and tobacco?
— A tax rate would be required that is high enough to discourage consumption but low enough to deter the black market from undercutting legal sales — a balancing act tobacco regulators continue to juggle.
— How would Canada manage crucial border issues with a prohibitionist United States?
It's only a partial, yet daunting, list of policy questions, with plenty of political risk.
Michel Perron, CEO of the government-funded Canadian Centre for Substance Abuse, expresses his anti-legalization position in terms of the precautionary principle.
"Our default position is let's not put any more genies out of the bottle," said Perron. "Let's try to ensure we can manage best what it is we're doing and how we work it."
Perron argues some of the perceived benefits of legalization would be lost in implementation.
"Put another way, simply legalizing marijuana is not going to address many of the problems that they've raised."
For one thing, most people agree that any legalized pot regime would have age restrictions prohibiting younger consumers, similar to alcohol. So enforcement policies — and costs — would continue under the new model.
And as legalization advocate Oscapella observed in an interview: "As long as the United States prohibits cannabis, there will be a black market in Canada in relation of sales to the United States."
Severe penalties, and police interdiction, will still be needed.
How much less policing might cost under a legalized pot regime depends on how the system is structured, and who you ask.
Perron, coming at the issue from a substance abuse perspective, laments the vastly different conclusions arrived at by researchers with "competing interests" using largely the same data.
"It exacerbates an already highly politicized issue and sometimes creates a certain paralysis around it," he said.
Critics say that's a recipe for public policy inertia. Few would argue that almost 90 years of marijuana prohibition in Canada — with ever-increasing government efforts to deter its trade — has been a success.
Justice Minister Rob Nicholson's office said he was unavailable all week for an interview on the Liberal legalization proposal.
"That said, our government has no intention to decriminalize or legalize marijuana," said Nicholson's spokeswoman.
The Justice Department, however, has commissioned an evaluation of the Conservative anti-drug strategy, which provided a largely favourable report last September.
Obtained under Access to Information by The Canadian Press, the report's specific findings on the relevance and effectiveness of the strategy were blacked out. The report also twice lamented that the strategy "does not have specific measurable targeted outcomes."
It also noted that "regulatory deficiencies, the massive scope of the drug problem and limited resources of enforcement partners," all contribute to "gaps" in the Conservative government's enforcement plan.
Skeptics such as Perron of the Canadian Centre for Substance Abuse call legalization "an untested social experiment," but others insist there is a wealth of knowledge and experience at hand.
"They've been thinking about this for decades," said Haden, who works closely with B.C.'s health officer council.
"The work is being done now in anticipation of a legalized regime. We can start to talk about what it looks like."
Haden's assessment is sobering, nonetheless.
"We do understand some regulatory principles around lots of things. We understand from alcohol and tobacco. We can learn the lessons from there and say: Big mistake, let's not replicate that error."
— With files from Steve Rennie
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