Canada wants to legalize marijuana — and it may be willing to break international law to do it.

On Thursday, the ruling Liberal Party in the Canadian Parliament introduced a bill that would legalize marijuana for recreational purposes. It would be the first developed country in the world to fully legalize pot since the international war on drugs began in the 1970s.

The bill will set the minimum age for purchasing marijuana at 18, although provinces could raise the age within their borders. The federal government will handle licensing producers, while provincial governments will manage distribution and retail sales. And Canadians will be allowed to grow up to four marijuana plants per household and possess up to 30 grams per person. For the most part, the bill follows the recommendations made by a recent federal task force on marijuana legalization — although the bill could change as it works its way through Parliament.

None of this should seem too shocking in the US, where already eight states have legalized marijuana for recreational use and 28 have allowed cannabis for medicinal purposes. What sets Canada apart, though, is it’s doing this as a country. Currently, Uruguay is the only nation in the world that legally allows marijuana for recreational purposes.

This is an important distinction from state-by-state legalization because Canada, like the US, is part of international drug treaties that explicitly ban legalizing marijuana. And although activists have been pushing to change these treaties for years, they have failed so far — and that means Canada will be, in effect, in violation of international law when it moves to legalize. (The US argues it’s still in accordance with the treaties because, even though the federal government allows marijuana legalization to continue at the state level by taking a hands-off approach, federal law still technically prohibits cannabis.)

Still, the move is, according to advocates of legalization, long overdue. When Liberal Prime Minister Justin Trudeau’s party was elected in 2015, one of the main promises he ran on was to legalize marijuana. But the process of actually beginning to legalize stalled as the government waited on the task force report on legalization, and finally put a bill together based on the recommendations.

“We will legalize, regulate, and restrict access to marijuana,” Trudeau’s Liberal Party declared on its campaign website. “Canada’s current system of marijuana prohibition does not work. It does not prevent young people from using marijuana and too many Canadians end up with criminal records for possessing small amounts of the drug.”

The bill, of course, is not law just yet. It will need Parliament’s approval — which may require wrangling some changes to get — to become law. But the bill’s chances seem good: Liberals control a majority of the House of Commons, and on legalization they’re backed by the even more liberal New Democratic Party. Conservatives ran in opposition to legal pot, but at this point they are a fairly small minority in the Canadian government. Still, the bill may face some hurdles in the independent Senate, a legislative body that traditionally is more ceremonial in function but is recently doing more to assert its authority.

In moving forward, the Canadian government is now walking a fine line: It is hoping to legalize marijuana to clamp down on the black market for cannabis and provide a safe outlet of cannabis for adults, but it’s risking making pot more accessible to kids and people with drug use disorders. It is taking a bold step against outdated international drug laws, but it could upset countries like Russia, China, and even the US that have historically adopted a stricter view of the treaties. And while Canadian lawmakers may feel marijuana legalization is right for their country, there’s a risk that legal Canadian pot will spill over to the US — perhaps causing tensions with Canada’s neighbor and one of its closest allies.

Whether Canada is successful in its legalization attempts will depend on how it strikes a balance between these concerns. And depending on how it pulls all of this off, it may provide a model to other countries interested in legalization — including the US.

Legalization is a balancing act

The argument for full legalization is really about striking the right balance for drug policy.

On one hand, marijuana prohibition has a lot of costs. In Canada, tens of thousands of people are arrested for marijuana offenses each year, ripping communities and families apart as people are thrown in jail or prison and gain criminal records. Enforcement of these laws also costs money, while legalizing and taxing marijuana could bring in extra revenues — although typically not that much, based on Colorado’s experience, where marijuana taxes make up less than 1 percent of the general budget.

And the black market for marijuana fuels violence around the world — not only can it lead to conflicts and violence within Canada, but the money from illegally produced and sold pot often goes back to drug cartels that then use that money to carry out brutal violence, including murders, beheadings, kidnappings, and torture.

Better access to marijuana could also reduce the use of deadly opioids. The research shows that marijuana is promising for treating chronic pain, something that opioids are often prescribed for (even though there’s no good evidence opioids can actually treat chronic pain, while there’s evidence they can in fact make pain worse). Since marijuana doesn’t carry the risk of deadly overdose and opioids do, replacing some opioid use for pain with pot use could save lives. Studies show that states with medical marijuana laws suffer fewer opioid deaths than they otherwise would.

Still, since Canada already has medical marijuana, it’s possible full legalization won’t have much of an impact when it comes to opioid use.

Legalization carries risks too. It could lead to more use and misuse by making pot cheaper and more available. Mark Kleiman, a drug policy expert at New York University’s Marron Institute estimates that in the long term a legal marijuana joint will cost no more to make than, say, a tea bag — since both products come from plants that are fairly easy to grow. And it would also be available to anyone (of legal age) in retail outlets after legalization — meaning it would no longer require a shady or secretive meeting with a drug dealer. Those are benefits for responsible marijuana users, to be sure, but easier access could also be a risk for those who aren’t responsible.

And although marijuana isn’t very dangerous compared to some drugs, it does carry some risks: dependence and overuse, accidents, non-deadly overdoses that lead to mental anguish and anxiety, and, in rare cases, psychotic episodes. Still, it’s never been definitively linked to any serious ailments — not deadly overdoses, lung disease, or schizophrenia. And it’s much less likely — around one-tenth so, based on data for fatal car crashes — to cause deadly accidents than alcohol, which is legal.

Among the risks, drug policy experts emphasize the risk of dependence. As Jon Caulkins, a drug policy expert at Carnegie Mellon University, has told me, “At some level, we know that spending more than half of your waking hours intoxicated for years and years on end is not increasing the likelihood that you’ll win a Pulitzer Prize or discover the cure for cancer.”

Another concern is the research on marijuana is still fairly weak. For years, there have been strict regulatory hurdles to marijuana research in the US due to prohibition, and that’s inhibited major studies on the drug’s long-term benefits and risks. It’s possible that with more study, new risks will surface — especially since legal marijuana markets may lead to more potent forms of the drug, which could carry unique problems.

“We’re still learning a lot about the health consequences,” Beau Kilmer, a drug policy expert at RAND, told me. “The bulk of the research that gets quoted in marijuana legalization debates is based on people who smoked relatively low-potency marijuana in the ’80s and ’90s. So we still have a lot to learn.”

To this end, legalization in Canada may help us better understand pot — by giving us another source of legal marijuana to study.

Despite the noted risks, drug policy experts generally agree that marijuana is relatively safe compared to other drugs, including legal substances like tobacco and alcohol.

Legalization is about balancing all of these concerns. It’s not necessarily about formally embracing pot use, but saying that perhaps the cons of keeping cannabis illegal simply outweigh the cons of making it legal. Striking that balance will be Canada’s big goal as it moves forward with its legalization bill.

Canada is following a different legalization track than the US

Canada is working on striking this balance in a very different way than the states that have legalized so far in the US. Primarily, it seems to be emphasizing public health far more than states in America have.

So far in the US, the eight states that have legalized pot have done so with a model similar to alcohol. Basically, they’re setting their systems up to allow a for-profit pot industry to flourish, similar to the alcohol industry.

Drug policy experts, however, often point to the alcohol industry as a warning, not something to be admired and followed for other drugs. For decades, big alcohol has successfully lobbied lawmakers to block tax increases and regulations on alcohol, all while marketing its product as fun and sexy in television programs, such as the Super Bowl, that are viewed by millions of Americans, including children. Meanwhile, alcohol is linked to 88,000 deaths each year in the US.

If marijuana companies are able to act like the tobacco and alcohol industries have in the past, there's a good chance that they’ll convince more Americans to try or even regularly use marijuana, and some of the heaviest users may use more of the drug. And as these companies increase their profits, they’ll be able to influence lawmakers in a way that could stifle regulations or other policies that curtail cannabis misuse. All of that will likely prove bad for public health (although likely not as bad as alcohol, since alcohol is simply more dangerous).

There are policies that can curtail this, some of which Canada’s plan will allow.

For example, Canada’s measure restricts marketing and advertising. In the US, this is generally not possible because the First Amendment protects commercial free speech. (Tobacco marketing is largely prohibited due to a massive legal settlement.) But in Canada, the restrictions could stop marijuana companies from marketing their product in a way that targets, say, children or people who already heavily use cannabis.

“It’s a no-brainer,” Caulkins said. For public health purposes, “every serious researcher around the world thinks it’s a very good idea to restrict advertising of tobacco, alcohol, any dependence-inducing substance.”

Canada’s bill also lets provinces entirely handle the distribution and sales of marijuana — up to letting provincial governments directly manage and staff all pot stores by themselves. Again, in the US, this is currently not possible: Since marijuana is illegal at the federal level, asking state employees to run marijuana shops would effectively force them to violate federal law. But since Canada is legalizing marijuana nationwide in one go, it can do this.

The promise with government-run marijuana shops is that they could be better for public health. In short, government agencies that run shops are generally going to be more mindful of public health and safety, while private companies running shops are only going to be interested in maximizing sales even if that means making prices very low or selling to minors and people with drug use disorders. Previous research found that states that maintained a government-operated monopoly for alcohol kept prices higher, reduced youth access, and reduced overall levels of use — all benefits to public health.

Again, this is about balancing the risks and benefits of legalization: Maybe legalization is the better approach on net compared to prohibition, but that doesn’t mean that for-profit, private companies have to be the ones to sell the drug.

This isn’t important just to Canada. If Canada shows that these policies — and the many other quirks that will make it different to the US — are the right approach to legalization, it could provide a legalization model to the rest of the world that’s very different from what America has done so far.

A big hurdle for Canada: international drug treaties

If one thing holds up Canada’s plans, it may be international law.

From the 1960s through the 1980s, much of the world, including the US and Canada, signed on to three major international drug policy treaties: the Single Convention on Narcotic Drugs of 1961, the Convention on Psychotropic Drugs of 1971, and the UN Convention against Illicit Traffic in Narcotic Drugs and Psychotropic Substances of 1988. Combined, the treaties require participants to limit and even prohibit the possession, use, trade, and distribution of drugs outside of medical and scientific purposes, and work together to stop international drug trafficking.

There is some debate about whether these treaties stop countries from decriminalizing marijuana — when criminal penalties are repealed but civil ones remain in place — and legalizing medical marijuana. But one thing the treaties are absolutely clear on is that illicit drugs aren’t to be allowed for recreational use and certainly not for recreational sales. Yet that’s exactly what the Liberal Party is now working to allow.

Canada’s decision to legalize pot would be the most high-profile rebuke of the international treaties since they were signed — since Canada is a relatively large developed country, and it’s fairly active in the international arena.

In theory, Canada could face diplomatic backlash if it legalizes pot. But who would lead that effort? The US has been the de facto enforcer of international drug treaties over the years. But it likely wouldn’t tempt an important ally, and trying to criticize Canada for legalization would only expose America’s hypocrisy for letting eight states legalize.

One possible issue could be marijuana flowing from across the border from Canada. The experts I talked to argued there might not be too much of this, given that the US has its own legal supplies for pot from the states that have legalized for recreational and medicinal purposes. But if the US sees a risk in Canadian pot smuggling and reacts, it’s not totally out of the realm of possibility that someone like President Donald Trump would try to crack down at the border — and maybe cause problems with a huge trade partner.

“Given the importance to Canada of US-Canadian trade, they’re not going to want to do anything that leads the US to thicken the border,” Kleiman of the Marron Institute told me.

There’s one way Canada could get around the treaty problem. In the early 2010s, Bolivia moved to allow coca leaf chewing, which was banned from the treaties. To get around this, the country effectively withdrew from the 1961 Single Convention on Narcotic Drugs, then it rejoined with a “reservation” allowing the use of coca leaves within its own borders. The move could have been blocked by one-third of the parties to the treaty — which would amount to more than 60 nations — but only 15 joined in opposition.

Canada could use a similar process — of withdrawing then rejoining with a reservation for legal pot — to meet its treaty obligations.

Canada could also follow Uruguay, which has essentially refused to acknowledge that legalization violates the treaties (even though it clearly does). Despite warnings from the UN Office on Drugs and Crime, no one has taken significant action against Uruguay for its decision.

As for the US, it claims accordance of the drug treaties, despite eight states’ move to legalize marijuana, with a clever argument: It’s true that eight states have legalized pot, but the federal government still considers marijuana illegal, so the nation is still technically in line, even if a few states are not. Canada could not try this route if it legalizes nationwide.

“A lot of people are going to be paying attention to how the United States reacts — or does not react — to what Canada does,” Kilmer said. “I think that could actually have implications in other countries.”

If Canada pulls this off, it could provide a model for other countries to relax their drug laws — and particularly their marijuana laws — without violating international treaty obligations or, at the very least, without getting punished for disobeying the treaties.

Such a move would come at a very crucial time in international drug policy: After the UN’s special session on drugs in 2016, drug policy reformers are putting more and more pressure to reform the global drug control regime. Canadian legalization could give these reformers an opening by showing that if the treaties aren’t changed, they will soon be effectively meaningless as countries move ahead with their own reforms anyway — even if it puts them in violation of international drug law. And that could open up the rest of the world to legalizing pot.

It’s not just, then, that Canada is changing its own drug laws. Canada’s steps — from its rebuke of international drug treaties to how it will regulate cannabis — could affect the future of marijuana policy worldwide.