The International Narcotics Control Board is expressing concerns about the Trudeau government's plan to legalize recreational cannabis use in Canada, warning the move will place Canada in violation of international drug control conventions.

The board reaffirmed its opposition in its newly-released 2017 report, which states that using cannabis for anything other than medical or scientific purposes would be a violation of conventions Canada has signed.

"As the board has stated repeatedly, if passed into law, provisions of Bill C-45, which permit non-medical and non-scientific use of cannabis, would be incompatible with the obligations assumed by Canada under the 1961 Convention as amended," the report said.

Canada signed three UN conventions prohibiting the production, possession and consumption of drugs, including cannabis. Despite numerous warnings, the Trudeau government has not revealed how it plans to stay in compliance with the conventions.

"Right now, we have a total lack of strategy," said Bruno Gélinas-Faucher, a doctoral candidate in international law at the University of Cambridge and a lecturer at the University of Montreal.

He said Ottawa must quickly clarify its intentions to avoid harming its image and its credibility on the international stage — and warns that the legalization project could jeopardize Canada's chances of getting a seat on the United Nations Security Council.

Canada's leadership role

"We should have done our homework in advance. This is not something new. It is a commitment that Mr. Trudeau took before the 2015 campaign," said NDP MP Matthew Dubé.

Canada could withdraw from the agreements with the intention of re-joining them at a later date — but it's too late now to withdraw from the treaties before legalization takes effect, since they require a notice of withdrawal six to 12 months in advance.

The federal government also could ask the World Health Organization to look into reclassifying cannabis in international treaties.

Dubé said Canada should "play a leadership role" in modernizing these agreements.

For the moment, however, the Liberal government has yet to clarify its approach to these treaties.

Punishments limited

Adam Austen, a spokesman for Foreign Affairs Minister Chrystia Freeland, said that experts have been consulted to "determine the best way forward for our international commitments." But he offered no guidance on how Canada will meet its obligations.

"We are committed to working with our global partners to better promote public health and the fight against illicit drug trafficking," he said.

While Canada appears set to violate these international agreements, the board has limited powers when it comes to forcing signatories to comply.

Gélinas-Faucher said that the agency can ask countries which signed these agreements to discontinue their drug trade with Canada, since the agreements govern trade in legal drugs as well. And another country could sue Canada before the International Court of Justice.

Those scenarios, however, are considered unlikely. Uruguay, which also legalized cannabis, has not been subjected to similar reprisals.