US-Canada Trade War (2025-2026)

One-line summary: A year-old, ongoing trade conflict triggered by Trump's February 2025 tariffs that has reorganized North American economic flows, hit Canadian manufacturing hard while leaving US growth largely intact, and survived a Supreme Court ruling against the original IEEPA authority — now organized around a fragile CUSMA-shielded equilibrium awaiting the July 2026 review.

The insight

Three structural facts about this trade war are persistently underappreciated and worth holding together:

1. The damage is asymmetric. US aggregate growth is forecast at ~2.2-2.4% in 2026 vs Canada's ~1.3-1.4%. The US absorbs the conflict diffusely; Canada absorbs it concentrated by sector and province.
2. CUSMA is the load-bearing structure. ~90% of Canadian exports flow tariff-free because of CUSMA-compliance — without it, the deceleration becomes a recession. The July 2026 review is therefore the largest visible cliff.
3. The legal architecture has shifted under the Supreme Court ruling. On February 20, 2026 SCOTUS struck down IEEPA-based tariffs (eliminating ~$95.8B in 2025 collections); Trump replaced them with a 10% Section 122 universal tariff (150-day expiry). Sector-specific Section 232 tariffs (steel 50%, aluminum 50%, autos 25%, lumber stacking) survived the ruling and remain in force.

Evidence

From 2026-04-21-autoresearch-canada-us-tensions-economy-2026:

Tariff timeline (key dates)

• Feb 1, 2025: Trump signs IEEPA tariffs of 25% on most Canadian goods, 10% on energy/potash, citing fentanyl. Trudeau immediately announces CA$155B in retaliatory tariffs.
• March 4, 2025: Tariffs implemented; S&P 500 falls 1.8%, Nasdaq 2.6%.
• March 6, 2025: 30-day reprieve for CUSMA-compliant goods (≈38% of Canadian exports).
• March 11–12, 2025: Trump doubles steel/aluminum tariffs to 50% after Ontario threatens electricity tariffs.
• March 14, 2025: mark-carney sworn in, confirms continuation of retaliation.
• April 3, 2025: 25% global auto tariff effective. Stellantis idles plants in Canada/Mexico, lays off 900 US workers.
• June 4, 2025: Steel/aluminum doubled to 50%.
• August 1, 2025: 35% IEEPA tariff on non-USMCA goods (allegedly tied to Palestinian-statehood-recognition diplomacy).
• October 25, 2025: Additional 10% increase on broad goods, in retaliation for an Ontario advertising campaign.
• January 16, 2026: canada-china-trade-deal-2026 announced. Trump threatens 100% tariffs on all Canadian goods on January 24.
• February 20, 2026: SCOTUS rules 6-3 that IEEPA does not authorize tariffs. Trump replaces with 10% Section 122 universal tariff on ~$1.2T of imports (150-day expiry).
• April 19, 2026: Carney calls US trade ties "weaknesses that must be corrected."
• July 2026: CUSMA joint review scheduled.

Tariff state as of April 2026

Sector-by-sector (2026-04-21-autoresearch-canada-us-tensions-economy-2026):

• Steel: 50% (doubled June 2025)
• Aluminum: 50%
• Autos and parts: 25% (with US-content carve-outs)
• Energy and potash: 10%
• Lumber: 10% softwood, 30% upholstered furniture, 50% cabinets/vanities (stacking effective Jan 1 2026)
• CUSMA-compliant general goods: broadly exempt
• Non-CUSMA general goods: 10% (Section 122, expires after 150 days from imposition)

US aggregate effective tariff rate hit 7.7% in 2025 — highest since 1947. Post-SCOTUS weighted average is 6.7% — still highest since 1972. About $41 billion of Canadian imports are subject to US tariffs annualized.

Canadian retaliation (CA$30B at 25% from March 2025 + CA$29.8B targeting steel/aluminum from March 13 + matching 25% auto tariffs from April 9) remains in effect under the "no exemption for CUSMA-compliant goods means no exemption from us" principle.

Macro impact (asymmetric)

US side:

• Long-run GDP impact: -0.4% (Tax Foundation, combined Section 232 + IEEPA-replacement + retaliation)
• Employment effects: -154k FTEs (Section 232 alone), -141k from foreign retaliation
• Tariff-attributable inflation: ~2.7% PCE in 2026 vs ~2.24% counterfactual
• Per-household cost: $570 average in 2026 (Yale Budget Lab) — was projected ~$1,300 with IEEPA before SCOTUS
• 2026 GDP growth: 2.2-2.4% (multiple forecasts)

Canada side (canada-vs-us-economic-divergence-2026):

• 2026 GDP growth: 1.3-1.4% — deceleration from 1.7% in 2025
• Unemployment: 6.7%
• Steel exports collapsed 30% in the first year of tariffs (canadian-provincial-divergence-2026)
• Canada avoids recession across all forecast scenarios (RBC), but the impact concentrates in specific provinces severely

Compounding-shock framing (May 2026 update)

• From 2026-05-11-odd-lots-the-bank-of-englands-megan-greene-on-monetary-policy (Megan Greene, BoE MPC, listing the sequence of shocks driving inflation persistence): "we talk about the compounding effects of all these shocks (including the trade war and Brexit)" — the US-imposed trade-war regime is being explicitly counted by a sitting external MPC member as one of the four 5-year-period supply shocks (alongside Covid, Ukraine, Iran). This matters for political-economy reading: the trade war is not just a bilateral US-Canada dispute, it's part of a global central-bank-tracked supply-shock sequence whose persistence is the binding monetary-policy constraint in 2026. Cross-link: supply-shock-inflation-persistence (stock-market) for the behavioral substrate making each successive shock less transitory than the last.
• From 2026-05-14-odd-lots-martin-wolf-on-the-terrifying-superpower-the-us-wields (Martin Wolf, FT, on the Trump-coalition strategic-incoherence frame): "I see a separation between Donald Trump as a person... and his views of the world from that of the various different elements of the coalition that he's put together... I don't think the MAGA movement, broadly defined, knows what it wants." Trump's tariff posture is framed not as a coherent industrial-policy strategy but as a manifestation of bilateral-relations-as-personal-dominance preference: "he will throw his weight around, particularly against anybody who thinks he's essentially not showing him proper respect in various different ways." Wolf's reading would predict that tariff levels and exemptions track Trump's personal grievances and respect signals rather than economic logic — useful as a falsifiable hypothesis. Note Wolf himself frames the US under this regime as "a completely bewildering superpower" that other countries have to plan around without being able to predict.

Strategic reorientation by Canada

• Canadian merchandise exports to non-US markets surged 17% YoY through January 2026; US-bound exports fell 10%.
• By May 2025, Canada was exporting more crude to China than to the US.
• Canadian inbound FDI hit CA$96.8 billion in 2025 — highest since 2007, despite the trade war.
• Federal budget targets doubling non-US exports by 2035.
• See canada-china-trade-deal-2026 for the most visible diversification move.

Carney's framing has hardened

• Early 2025: relationship shift is "a rupture, not a transition" in the rules-based global order.
• April 19, 2026: Canada's close trade ties to US are "weaknesses that must be corrected"; US has raised tariffs to "levels last seen during the Great Depression."

Design implications for the politics thread

• Watch the July 2026 CUSMA review as the next visible inflection point. The current "manageable damage" framing depends on it surviving.
• Watch the Section 122 expiry (150 days from imposition). Trump will need new tariff authority — that's a forcing function for either negotiation or escalation.
• Watch Ontario / Quebec political dynamics. Provincial divergence inside Canada is the most underappreciated dimension; if those provinces' job losses compound, it pressures Carney's federal coalition (see canadian-provincial-divergence-2026).
• Track real US household pain. $570/year average is below the political-pain threshold; if 2026 H2 prices climb faster as inventory depletes (per the Fed's "Slow Climb" finding), the politics shift.

Contradictions / tensions

• "Manageable" vs "rupture" framings coexist. RBC says Canada is "more resilient than feared" with first per-capita GDP increase in three years; RSM ranks Canada the worst performer of US/UK/Canada/Australia comparison set; Carney calls it a rupture in the global order. All have different truth-conditions and audiences.
• The tariff inflation hit on US consumers is gradual. Per the Fed's "Slow Climb" paper (March 2026), retail prices "roughly until August" 2025 showed no significant reaction, then climbed steadily through year-end as inventory depleted. The political consequences may lag the economic ones.
• Canada's diversification narrative vs structural reality. 17% YoY non-US export growth is real, but the US still dominates Canadian trade flows. The Canada-China deal is a sliver, not a substitute.

Open questions

• Will the July 2026 CUSMA review be substantive (renegotiation) or procedural (renewal)?
• If Section 122's 150-day clock expires without congressional action, does the US lose its remaining IEEPA-substitute tariff authority?
• How much of Canada's reorientation toward non-US markets is durable vs reversible if a deal is struck?
• Does the trade war structurally widen the pre-existing per-capita gap, or is the cyclical effect separable from the structural one?

Public opinion dimension (added 2026-04-22)

Per 2026-04-21-autoresearch-trump-derangement-syndrome-canada, Canadian public opinion on Trump shifted sharply after the February 2025 tariff implementation — not before. Canadian Trump favorability fell from roughly 2024 baseline levels to 14–22% across 2025–2026 polls. The sentiment is chronologically a response to the trade war, not a cause of it. See canadian-anti-trump-sentiment for the polling trajectory, the cross-country allied-cluster comparison (Canada sits in line with Germany/UK/France/Italy, higher than Denmark/Mexico), and the boycott-behavior data ($3B Quebec travel-loss to the US, Brown-Forman -60% Canadian sales, 71–76% YoY flight-booking decline, etc.). This establishes the demand-side of the trade war — Canadian citizens diverting consumption and travel away from US businesses independently of government tariffs.

Related

• donald-trump — the US president driving the tariff campaign and rhetorical posture.
• mark-carney — Canadian leader managing the conflict.
• cusma — load-bearing exemption structure.
• canada-china-trade-deal-2026 — the biggest single Canadian diversification move and the trigger for Trump's January 100% threat.
• canada-vs-us-economic-divergence-2026 — structural backdrop the cyclical conflict sits on top of.
• canadian-provincial-divergence-2026 — Ontario/Quebec vs Alberta/Saskatchewan asymmetric pain.
• canadian-anti-trump-sentiment — the public-opinion and boycott-behavior dimension.
• canadian-decline-indicators — partisan compendium that overlaps with several of these economic claims (currency, per-capita gap).

Sources

• 2026-04-21-autoresearch-canada-us-tensions-economy-2026
• 2026-04-21-autoresearch-trump-derangement-syndrome-canada — for the public-opinion dimension cross-link.