Jane Philpott is celebrating 420 by trying to blow a hole through three United Nations treaties on narcotics.

"We know it is impossible to arrest our way out of this problem," Philpott told the United Nations General Assembly Special Session on drugs on Wednesday morning, which happens to be the counterculture holiday devoted to smoking weed.

Philpott is Canada's health minister, and she's become an unlikely champion for marijuana policy reform at the UN.

She also made a long-awaited announcement on Wednesday — Canada would move to fully legalize marijuana before 2018, a year and a half after they were first elected.

"We will introduce legislation in Spring 2017 that ensures we keep marijuana out of the hands of children and profits out of the hands of criminals," Philpott said.

The meeting, which bears the less-than-catchy acronym of UNGASS, has been a clash of ideologies, as hard-line prohibition states like Indonesia, which still executes drug dealers, meet countries like Canada.

"We will be saying, with the matter of marijuana, as all other drugs, we want to look at it — I will be looking at it — from the lens of public health," Philpott told VICE News on Tuesday.

On Philpott's agenda: legal marijuana, safe injection sites, and harm reduction policies that have been shunned by many of the other nations that will be around the table.

Philpott's Liberal government campaigned aggressively on legalizing marijuana, making it the first successful national party in Canada to do so, but criticism is growing over continued arrests, raids, and prosecutions over simple marijuana possession back home.

Here's what Canada plans to tell the UN about legalizing weed — VICE Canada (@vicecanada)April 20, 2016

The last UNGASS focusing on drug policy was 18 years ago. Then, member states promised to strive for "a drug-free world." They recommitted to three conventions that dictate how states are expected to combat and criminalize production and drug trafficking.Those conventions are now causing headaches for normally treaty-abiding countries like Canada.

"The first step in working towards how we're going to respond to those treaties is making sure that we have an open dialogue, making sure they understand why Canada believes this will benefit our citizens, and I think that tomorrow's meeting is going to be a really instrumental step in that approach," Philpott said outside Ottawa's Parliament buildings.

How Philpott intends to turn that dialogue into an actual change in policy at the UN is still an open question. A briefing note prepared for the prime minister on this issue from 2015, obtained by VICE News under access to information laws, reads that "Canada will need to explore how to inform the international community and will have to determine the steps needed to adjust its obligations under these conventions."

But anyone expecting flexibility from the International Narcotics Control Board (INCB) — the body tasked with overseeing the conventions — might find it lacking. A 2014 report singled out the government of Uruguay, which moved to legalize marijuana that year, writing that the board "urges the Government of Uruguay to take the necessary measures to ensure full compliance with those treaties."

Renegotiating those treaties is not on the agenda for Wednesday's meeting.

Canada could choose to simply ignore the conventions altogether. The INCB is largely toothless and — aside from issuing reports — there's not too much it can actually do. The conventions are, technically, binding, but they don't offer any recourse to punish a country that ignores them.

Nevertheless, Ottawa seems determined to preserve all the political capital it can get, as it sets up a bid for a non-permanent seat at the UN Security Council.

Thus far, the meetings at UNGASS have not inspired confidence. A representative from the INCB clearly told other states on Tuesday morning that the three conventions expressly forbid marijuana legalization, and suggested that there's little room for interpretation.

But there's some room for hope for countries like Canada.

Two of the world's sheriffs in the war on drugs — America and Mexico — may be looking to hang up their spurs. While neither has flatly come out and endorsed legalization outright, a patchwork of American jurisdictions have legalized the drug (again, drawing ire from the INCB) while Mexico's president told the assembly on Tuesday that it could be open to legalizing medical marijuana.

"This is an opportunity for us to have a respectful dialog with our international counterparts," Philpott said. "They are very interested in the reasons why we've decided that this is the right approach. We will talk a lot about what our common ground is. Where we agree with one another."

She also noted other comments from the international narcotics board. "I was heartened by the INCB President's recent reminder to us that we must put health and welfare at the centre of a balanced approach to treaty implementation," she told the special assembly on Wednesday.

There's also lots of room to disagree.

Countries like Russia and China have little interest in liberalizing their drug policies, while Indonesia spoke out at Tuesday's UNGASS meeting to insist that the UN has no business interfering with its policy of executing some drug traffickers. Attempts to include language decrying the use of the death penalty for drug crimes ultimately failed.

That hasn't stopped Canada from advancing on other fronts, though.

"I hope we will see our government push for changes and more flexibility in the conventions. The conventions were adopted far too long ago and they don't reflect the current evidence when it comes to drugs."

When asked whether supervised injection sites, needle exchanges, and other harm reduction measures would be on Canada's agenda for the UNGASS meeting, Philpott replied: "Very much so."

Harm reduction programs were obliquely encouraged by the drug summit, although the summit has deliberately avoided the words "harm reduction."

"I have a degree in public health. I'm very supportive of a public health approach to drug policy and harm reduction is one of the fundamental pillars of that," she said. "I am very much in favour of public health policies that will make sure people have access to care, that lives are saved, and that we prevent infection."

Canada's submission to the UN in March, which was supposed to lay the groundwork for Wednesday's summit, made scant mention of using the criminal justice system, except to say that "above all, Canada believes that any drug policy should be rooted in the recognition of and respect for human rights and that sanctions for crime, including drug-related crime, should be proportionate to the nature of the offense." That statement reiterated: Canada will legalize, regulate, tax, and sell marijuana.

But while Philpott's comments at the UNGASS are expected to serve as a rallying cry for other countries to follow, and to offer backing for smaller countries like Uruguay, there's some criticism from an unlikely place — within her own party.

Nathaniel Erskine-Smith, a Member of Parliament for a downtown Toronto riding, elected in an upswell of support for Prime Minister Justin Trudeau's Liberal Party during the last federal election.

He's been vocal about how he feels about the government's current work on marijuana legalization.

"I'm frustrated," Erskine-Smith told VICE News.

While statistics aren't yet available, there has been no evidence that arrests and prosecutions for marijuana possession have stopped or even abated since Trudeau's Liberals were elected last October.

"My first request was: We should decriminalize it. They said, 'No, the law is the law is the law,'" he said. His next suggestion, to instruct prosecutors to simply stop trying marijuana cases, went unheeded by the government.

"I'm very happy to be part of a government that's also committed to safe injection clinics and an evidence-based approach, a harm reduction approach, more than anything," he said, adding that he wants to see his government halt prosecutions for possession of marijuana while they worked on legalization.

A perfect place to start, he said, would be in New York during UNGASS.