Canada became the first wealthy nation in the world to fully legalize marijuana.

The Senate passed Bill C-45, also known as the Cannabis Act, on Tuesday. The measure had already been approved by the House of Commons, so Senate approval means it is now ready to become law.

The measure legalizes the possession of marijuana, the cultivation of plants at home and sales to adults. The federal government will oversee remaining criminal sanctions (for example, sales to minors) and manufacturer licensing, while provincial governments will manage sales, distribution and related regulations - as such, provinces will be able to impose more stringent regulations. severe, such as increasing the minimum age. The law largely follows recommendations made by a federal task force on marijuana legalization.

Canadian and provincial governments are expected to need two to three months before retail sales and other parts of the law can be implemented.

None of this may seem too shocking in the United States, where nine states have already legalized marijuana for recreational use and 29 states have allowed it for medical purposes. What distinguishes Canada, however, is that legalization occurred at the country level and not at the individual state level as in the USA. Previously, the South American nation of Uruguay was the only one that legally allowed marijuana for recreational purposes.

Canada, like the United States, is a party to international drug treaties that explicitly prohibit the legalization of marijuana. Although activists have been pushing to change these treaties for years, they have failed so far — and that means Canada will, in effect, be in violation of international law in moving to legalization. (The United States argues that it is still in agreement with the treaties because federal law continues to technically ban cannabis, even though some states have legalized it.)

For Canada's ruling party, this fulfills an important campaign promise. When Prime Minister Justin Trudeau's Liberal Party was elected in 2015, one of the main promises it worked on was the legalization of marijuana.

“We will legalize, regulate and limit access to marijuana,” the Liberal Party said on its campaign website. “Canada's current marijuana prohibition system doesn't work. It doesn't stop young people from using marijuana and too many Canadians end up with criminal records for possessing small amounts of the drug.”

But the process languished as Trudeau and his allies awaited recommendations from a federal task force and the Senate debated several provisions of the bill.

Moving forward, the Canadian government is now walking a fine line: It hopes to legalize marijuana to crack down on the cannabis black market and provide a safe outlet for adults, but risks making the product more accessible to children and people with disorders. It is taking a bold step against outdated international drug laws, but it could upset countries like Russia, China and even the United States that have historically taken a tougher view of treaties. And while Canadian lawmakers may believe that marijuana legalization is right for their country, there is a risk that legal Canadian cannabis could spill into the United States causing tensions with Canada's neighbor one of its closest allies.

Whether Canada succeeds in its legalization efforts will depend on how it strikes a balance between these concerns. Additionally, depending on how legalization is structured, it can provide a model for other countries interested in legalization, including the United States.

The risks and benefits of legalization
For Canada, marijuana legalization has been a balancing act from the start.

On the one hand, marijuana prohibition has many costs. In Canada, tens of thousands of people are arrested for marijuana offenses every year, tearing communities and families apart as people are thrown into prison and face criminal records. Enforcing these laws also costs money, while legalizing and taxing marijuana could bring in extra revenue — though typically not that much, based on Colorado's experience, where marijuana taxes account for less than 1% of the budget general.

The black market for marijuana fuels violence around the world - not only can it lead to conflict and violence within Canada, but the money from illegally produced and sold pot often goes back to drug cartels who then use that money to carry out brutal violence, including murder, beheading, kidnapping and torture. Legalization moves marijuana from the illicit and potentially violent market to the legal one that can produce legitimate jobs.

Legalization also carries risks. It could lead to increased use and misuse by making Cannabis cheaper and more available. Mark Kleiman, a drug policy expert at New York University's Marron Institute, estimates that in the long run a joint of legal marijuana will cost no more than, say, a tea bag - since both products come from plants that are quite easy to grow. It would also be available to anyone (of legal age) at retail outlets after legalization – meaning it would no longer require an unpleasant or secret meeting with a drug dealer.

These are benefits for people who use marijuana without problems, to be sure, but easier access could also pose a risk for people who can't control their cannabis use.

Although marijuana is not very dangerous compared to other drugs, it carries some risks: addiction and excessive use leading to mental anguish and anxiety and, in rare cases, psychotic episodes. However, it has never been conclusively linked to any serious disorder - fatal overdose, lung disease or schizophrenia. And it is much less likely - about a tenth therefore, based on data relating to fatal road accidents - to cause fatal accidents than alcohol, which is legal.

Among the risks, drug experts highlight the risk of abuse and addiction. As Jon Caulkins, a drug policy expert at Carnegie Mellon University, told me, "At some level, we know that spending more than half of your waking hours intoxicated for years on end does not increase the likelihood that you will win a Pulitzer Prize or discover the cure for cancer."

A balancing act
To that end, Canada is striking a different balance than the U.S.'s legalization experiments thus far.

So far in the United States, the eight states that have legalized cannabis sales have done so with a model similar to alcohol. (Vermont only has legalized possession, not retail sales.) Basically, they are setting up their systems to allow a for-profit cultivation industry to thrive, 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 by other drugs. For decades, big booze has lobbied lawmakers to block tax increases and alcohol regulations, all while marketing its product as fun and sexy on television shows, like the Super Bowl, that are watched by millions Americans, including children. Meanwhile, alcohol is linked to 88,000 deaths each year in the United States.

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

There are policies that can reduce these risks, some of which are included in Canada's plan.

For example, Canada's measure limits marketing and advertising. In the United States, this is generally more difficult because the First Amendment protects commercial freedom of expression. (Tobacco marketing is largely banned due to a massive legal settlement.) But in Canada, restrictions could prevent marijuana companies from marketing their product in ways that target, for example, children or people who already they use cannabis heavily.

“It's a no-brainer,” Caulkins previously told me. For public health reasons, "every serious researcher in the world thinks it is a good idea to limit advertising of tobacco, alcohol, any addictive substance."

Canadian law also lets provinces entirely manage the distribution and sales of marijuana - to the point of letting provincial governments directly manage and operate all stores themselves. While in the United States liquor stores are never seen in alcohol, it is considered risky in America with marijuana: since cannabis is illegal at the federal level, asking state employees to operate marijuana shops could actually ask them to violate the federal law. But since Canada is legalizing marijuana nationwide in one go, it can do so — and several provinces should consider this option.

The promise of government-run marijuana shops is that they could be better for public health. In short, government agencies running stores are generally more concerned with public health and safety, while private companies will be interested in maximizing sales.

Previous research found that states that maintained a governed monopoly on alcohol kept prices higher, reduced youth access and reduced overall levels of use – all of which benefit public health.

Once again, it's about balancing the risks and benefits of legalization.

This is not just important for Canada but for the entire world. If Canada proves that these policies are the right approach to legalization, they could provide a legalization model to the rest of the world that is very different from what America has done so far.