The congressman noted that in 2020 the countries struck a deal to form the Canada-U.S. Joint Action Plan on Critical Minerals. President Joe Biden and Prime Minister Justin Trudeau have committed to strengthening critical minerals supply chains together.

“Was the Biden administration notified and, if it was, why did it green-light this acquisition?” said Waltz, who is a member of the House Committee on Science, Space and Technology. “And if it wasn't, why wasn't it in accordance with the agreement? Obviously, we're NATO allies. We, I think, have a common view of the Chinese Communist Party as an increasingly dangerous and threatening adversary.”

The background: Trudeau’s political opponents launched a study of the deal in Parliament, given that the Argentinian mine is expected to extract the critical mineral. A top security expert told POLITICO the decision is “headshaking” and a “grievous” mistake.

Government’s defense: Last week, Canadian Industry Minister François-Philippe Champagne defended the government’s actions on the deal, which closed last month.

“Transactions involving critical minerals are systematically and thoroughly reviewed and scrutinized,” Champagne told the House of Commons’ industry committee. “Neo Lithium was no exception. Let me be very clear: Neo Lithium was reviewed by the government and national security experts. Full stop.”

Security and intelligence agencies and other investigative bodies reviewed the Neo Lithium investment, the minister added.

Champagne, however, declined to explain what consultations he may or may not have had with U.S. officials about the transaction.

Simon Kennedy, deputy minister of Innovation, Science and Economic Development, told the same hearing he was not in a position to publicly discuss Canadian officials’ discussions with foreign governments, nor whether they did, or did not, happen.

Expert perspectives: Automotive Parts Manufacturers' Association President Flavio Volpe, who was part of the negotiations that produced the USMCA, told the committee last week that lithium from Argentina cannot be used in the production of vehicles in Canada, the U.S. or Mexico due to the trade deal’s compliance rules of origin.

“So, we're talking about a hypothetical use here that in practice would never happen,” Volpe said.

Security expert Wesley Wark, who also testified at the committee, told POLITICO that “the Neo Lithium mistake is a grievous one that is just headshaking.”

Wark said he believes it would be “absolutely standard practice” during the initial review stage for the Canadian government to reach out to U.S. officials to ask if they have any relevant information, or any views on the acquisition.

“I would be dumbfounded if there wasn't an American view expressed to Canadian officials,” said Wark, a senior fellow for the Centre for International Governance Innovation. “Of course, I have no idea what that view might have been.”

What's at stake: Waltz, a Green Beret and former Pentagon adviser, said Beijing has dominated critical minerals around the world for years, particularly lithium.

“It’s about having control over the supply,” said Waltz, the ranking Republican on the Armed Services Subcommittee on Readiness. “The Chinese Communist Party has repeatedly threatened to turn off our supply chains or to use our supply chains as geopolitical leverage… I would hope that Canada, our NATO allies and our Quad allies would stand alongside us.”

What’s next: Canada’s industry committee continues its critical minerals study Friday with testimony from academics and mining industry representatives.

The witness list includes Carleton University’s Meredith Lilly, who advised former Prime Minister Stephen Harper and Mining Association of Canada President Pierre Gratton.