Why now
The dependence is structural, and the relationship broke in 2025–26.
Canada sends roughly C$550 billion of goods a year to the United States — about 72% of all merchandise exports. Autos and parts are ~93% US-bound. Energy ~90%. Chemicals ~85%. Virtually 100% of pipeline natural gas and grid electricity physically cannot go anywhere else.
Between March 2025 and August 2026 the US imposed, in sequence: 25–35% blanket tariffs, 50% steel and aluminum tariffs, 25% auto tariffs, ~35% total softwood lumber levies — and in August 2026, the first-ever use of Section 338 of the Tariff Act: 50% tariffs on ~US$18–20B of Canadian goods, applying even to goods that qualify under the USMCA free-trade agreement. Negotiations collapsed August 21–22, 2026 (Carney suspended talks, vowing dollar-for-dollar retaliation); Canadian counter-tariffs took effect September 8, 2026.
The lesson is not that any one tariff is unbearable. It is that market access to the US can no longer be treated as a stable planning assumption — while every alternative buyer (EU, Japan, Korea, India, ASEAN) is actively signing agreements with Canada: CPTPP covers 99% of tariff lines with Japan and the UK, the Canada–Indonesia CEPA (signed 2025, in force expected 2026) will remove duties on 97% of current exports, and CETA with the EU sits chronically under-used (preference utilization on Canadian exports fell to 49.2% by 2024, down from 70.5% in 2021 — Global Affairs Canada chief economist, "Determinants of CETA preferential rate utilization (2018-2024)," July 2026 — vs 90%+ for mature FTAs).
Ottawa's stated target — announced October 2025 — is to double non-US exports within a decade — from ~C$220B to ~C$440B/yr by 2035. This site sets out what that actually requires, project by project, dollar by dollar.
Watch: why tariff wars have gone badly before
Four short, independent explainers on the last time a major economy tried this — included so the historical pattern isn't just asserted, it's shown.
These are independent third-party videos, included for historical context — they are not produced by or affiliated with this site, and inclusion here is not an endorsement of every claim made in them.