US-Canada Tariff Escalation Threatens North American Steel and Auto Supply Chains

The United States and Canada have escalated their trade dispute, imposing reciprocal tariffs that will directly impact North American steel and aluminum markets. The US recently levied duties on $20 billion of Canadian goods, including machinery and cement, effective August 22. In response, Canada announced counter-tariffs on sectors including steel, aluminum, and electronics, taking effect September 8.

Ottawa vowed to match Washington’s measures dollar for dollar. The Canadian government stated that existing counter-tariffs on steel and aluminum will jump from 25 percent to 50 percent to align with US rates. This rapid escalation leaves producers and importers scrambling to manage heightened uncertainty over material costs.

The complex reality of North American manufacturing means there will be no clear victor in this dispute. Many raw materials and components physically cross the border multiple times before final assembly. Consequently, businesses on both sides may end up paying these new duties multiple times on the same goods.

Atsi Sheth, chief credit officer at Moody’s Ratings, warned that the initial impact across all sectors will be chaos and a forced drive toward long-term supply chain shifts. While the larger US steel market holds a slight edge, the highly integrated automotive industry will suffer on both sides of the border. "For the auto sector, our view is that the sector is so integrated that the tariffs just don’t impact the country you are tariffing but your own country," Sheth noted.

The aluminum sector faces particularly steep hurdles for US domestic independence. During the first half of 2026, Canada supplied 60 percent of all unwrought aluminum imports into the US. Currently, the US produces approximately 750,000 tons of primary aluminum annually, leaving imports to satisfy roughly 85 percent of domestic demand.

Ewa Manthey, a commodities strategist at ING, emphasized that tariff policies alone cannot reshore aluminum production. "Restarts and expansions could narrow the gap, but new capacity takes years to permit, finance, build and ramp up," she said. Furthermore, the artificial intelligence boom complicates this domestic buildout, as data centers consume vast amounts of aluminum and compete directly with smelters for electrical power.

Achieving true supply chain independence demands more than just trade barriers. "If the goal is to reduce US reliance on imports, tariffs are only part of the answer," Manthey said. She added that the US also needs affordable power, infrastructure, long-term investment and policy certainty.