16. Steel Tariff Tensions: “National Security” Trade War
In 2018, the Trump administration imposed 25% tariffs on Canadian steel and 10% on aluminum, citing “national security concerns.” Canada, America’s closest military ally, responded with $12.6 billion in retaliatory tariffs. Trudeau called the security justification “insulting” given Canada’s military alliance. The dispute severely damaged relations until the tariffs were lifted in 2019. This conflict revealed how quickly trade disputes poison broader relationships.
