Trump's Latest Tariff Salvo Hits Canadian Mushrooms as CUSMA Review Looms

The Trump administration's latest round of tariffs targeting Canadian goods has put another agricultural sector in its crosshairs, with new duties on Canadian mushrooms set to take effect next week. The measure adds to existing US tariffs on Canadian steel, aluminium and softwood lumber and lands as the July 1 deadline approaches for the formal review of the Canada-United States-Mexico Agreement.

What was announced

The Trump administration informed Canadian counterparts last week that new tariffs on Canadian mushrooms would take effect in the coming days. The duties continue a pattern of targeted measures applied to specific Canadian sectors, often justified under national security or unfair trade provisions of US trade law.

Canadian mushroom producers are concentrated in Ontario and British Columbia and supply both domestic and US markets. The new duties will increase the price of Canadian mushrooms in the American market and could shift sourcing patterns away from Canadian suppliers if they remain in place for an extended period.

The wider tariff landscape

Trump has imposed tariffs on Canadian steel, aluminium and softwood lumber, and has labelled Canada a national security threat under US trade law. The cumulative effect of these measures has been to create persistent tension in a bilateral trading relationship that, only a few years ago, was widely considered to be one of the most stable in the world.

Canadian exporters in the affected sectors have responded with a combination of legal challenges, government-supported relief programs and diversification efforts toward European and Asian markets. The Carney government has rolled out support measures for the most exposed sectors, although those programs cannot fully offset the impact of sustained tariffs.

The CUSMA reviewThe most consequential trade question facing the Canadian government is the July 1 deadline for the formal review of CUSMA, the trade agreement that replaced NAFTA. Trump has repeatedly threatened to use the review to extract concessions on Canadian dairy market access, rules of origin in strategic sectors, and Canadian digital regulation that affects American technology platforms.

Canadian officials have prepared for the review with extensive consultations with industry, provinces and labour groups. The government has emphasised that the review is a structured process and that Canada will negotiate firmly to defend its interests. The outcome, however, remains uncertain.

The Jefferies forecast

In a recent note, the investment bank Jefferies put the odds of a clean renewal of CUSMA at just 10 per cent, with a 75 per cent probability that the agreement slides into a regime of annual reviews. That kind of structure would inject permanent uncertainty into the trading relationship and would complicate long-term investment decisions across multiple sectors.

Canadian and US business communities have generally favoured a clean renewal, citing the importance of stable trade rules for cross-border supply chains. Without that stability, capital allocation decisions are more likely to favour locations with more predictable trade regimes, a category that increasingly excludes North America.

Reaction from producers

The Canadian Mushroom Growers Association expressed concern about the new tariffs and called on the federal government to push back hard. According to the association, the measures will hurt small and medium-sized Canadian producers without delivering meaningful benefits to American consumers.

Industry representatives from other affected sectors have similarly warned that the cumulative effect of multiple rounds of tariffs is eroding Canadian competitiveness in the US market. Steel and aluminium producers have invested in alternative export channels but say the existing tariff regime continues to weigh on margins.

Reaction in Ottawa

Prime Minister Mark Carney met with President Trump in the Oval Office earlier this year, the first formal meeting between the two leaders. The meeting produced no significant breakthrough on the tariff file, although both sides described the conversation as constructive.

Cabinet ministers have continued to engage with American counterparts through formal and informal channels. Federal officials have also coordinated closely with provincial governments, particularly those representing the most exposed sectors, on responses ranging from financial support to legal challenges.

The Mexican parallel

US officials have, at the same time, been engaging with Mexico's top economic officials, leaving Canada to the side during certain rounds of discussion. The pattern has raised the possibility that the United States may pursue separate trade arrangements with its two neighbours rather than negotiate within the CUSMA framework as a single bloc.

For Canada, that prospect is both a risk and an opportunity. A separate American-Mexican track could weaken Canada's negotiating position by isolating Ottawa. It could also create space for Canada to push specific Canadian priorities without having to align with Mexican positions on every file.

The diversification effort

The Canadian government has been pushing diversification of trade relationships as a strategic response to American volatility. The recent Canada-Alberta agreement on a bitumen pipeline to Asian markets is one example. Trade missions to Europe, Asia and Latin America have also been more frequent.

Diversification, however, is a long-term project. The vast majority of Canadian goods exports go to the United States, and the integrated nature of North American supply chains in sectors such as automotive manufacturing cannot be replicated easily through trade with more distant partners. For now, Canadian exporters are managing the existing trade relationship while building options elsewhere.

The political dimension

The trade file has been one of the defining issues of the Carney government's early months. The Liberal government has framed its approach as one of firm but pragmatic engagement, neither escalating unnecessarily nor accepting unilateral American demands. The opposition has generally supported the principle of pushing back on tariffs while criticising specific elements of the government's approach.

Public opinion in Canada has hardened against the tariff campaign. Surveys consistently show large majorities of Canadians want the federal government to respond strongly to American measures and to support affected workers and sectors.

The provincial responses

Provincial premiers have generally supported the federal government's broad approach while pushing for specific support for their most exposed sectors. Ontario, with its automotive and steel exposure, has been particularly active in pressing for federal financial support. British Columbia, with its softwood lumber exposure, has similarly engaged closely with Ottawa. Alberta has pressed for energy sector cooperation and for protections against any future tariffs on Canadian crude.

The federal-provincial cooperation on trade has been more cohesive than on many other files, in part because tariff impacts cross political lines and affect every region. Premiers from all parties have generally backed federal pushback against American measures while seeking specific support for their constituents.

The automotive sector concern

The Canadian automotive sector, concentrated in Ontario, has been a particular focus of concern. The integrated North American automotive supply chain depends on tariff-free movement of parts and finished vehicles across the Canada-United States border. Sustained tariff disputes could disrupt that supply chain in ways that would affect employment, investment and consumer prices across multiple countries.

Automotive manufacturers have continued to invest in Canadian production, particularly in electric vehicle assembly and battery manufacturing. Several major investments have been announced over the past few years, including significant battery plant projects in Ontario and Quebec. The continuation of those investments depends, in significant part, on the broader trade relationship.

The Buy Canadian conversation

The trade tensions have fuelled a domestic conversation about Canadian-made goods, government procurement policy and consumer choices. Provincial and municipal governments have introduced or expanded preferences for Canadian suppliers in their procurement. Consumer awareness of country-of-origin labelling has grown, and Canadian-owned grocers have reported sustained interest in Canadian-sourced products.

The federal government has been more cautious about expanding formal Buy Canadian policies, in part because of international trade obligations and in part because of the practical difficulty of identifying which goods qualify in integrated supply chains. The political pressure for Buy Canadian initiatives, however, has continued to build.

What's next

The July 1 CUSMA review deadline is the next major milestone, although the precise sequence of events is uncertain. The federal government has signalled that it will engage in good faith negotiations while making clear that it will defend Canadian interests vigorously.

In the meantime, the mushroom tariffs and other recent measures will continue to ripple through specific sectors of the Canadian economy. The cumulative weight of the tariff campaign, combined with the broader uncertainty about CUSMA's future, will keep the trade file at the centre of Canadian economic and political conversations for the foreseeable future.