Last verified: August 26, 2026. This timeline separates measures that are in force, measures that have ended, and measures that have been announced but are not yet effective. That distinction matters: the broad emergency tariffs that dominated headlines in 2025 are no longer legally in effect, but sector tariffs have expanded and Canada has published a new retaliatory tariff list scheduled to take effect on September 8.

Canada and the United States have one of the world's largest bilateral goods relationships and deeply integrated energy, automotive, metals, agriculture, and manufacturing supply chains. Many products cross the border more than once before becoming a finished good. A tariff imposed at one stage can therefore affect producers and customers on both sides, even when the policy is formally directed at imports.

January–February 2025: the border emergency becomes a tariff policy

January 20, 2025 — Trump begins his second term

Donald Trump was inaugurated for a second term on January 20, 2025. The new administration quickly linked trade policy with border security and fentanyl enforcement. The administration's stated rationale was that extraordinary economic pressure was needed to obtain additional Canadian action at the northern border; Canada disputed the characterization of its role in U.S. fentanyl flows and emphasized measures already underway.

February 1 — a 25% border tariff is ordered

President Trump invoked the International Emergency Economic Powers Act, or IEEPA, to order an additional 25% tariff on most Canadian products and a lower 10% rate on Canadian energy resources. The order was initially scheduled to take effect on February 4. These duties were additional to ordinary customs duties and were not the same as the later steel, aluminum, automotive, or reciprocal-tariff actions. The White House fact sheet set out the administration's border and fentanyl rationale.

February 3 — implementation is paused for one month

The United States paused the tariffs until March 4 after Canada committed to reinforce its border response. The Canadian package included its previously announced C$1.3 billion border plan, additional personnel and technology, a fentanyl czar, and a Canada–U.S. joint strike force. The pause did not cancel the tariff order; it delayed its effective date while the governments continued discussions.

March 2025: tariffs take effect, then USMCA gets a carve-out

March 4 — U.S. tariffs begin and Canada retaliates

With no further extension, the IEEPA duties took effect: 25% on covered Canadian goods and 10% on covered Canadian energy resources. Canada immediately applied a 25% surtax to about C$30 billion of U.S. goods. The first Canadian list included products such as orange juice, peanut butter, wine, spirits, beer, coffee, appliances, apparel, footwear, motorcycles, cosmetics, and certain pulp and paper products. Ottawa also prepared a second, larger round after consultation, but it did not activate the full proposed C$155 billion package. Canada's March 4 announcement documents the scope and timing.

March 6–7 — qualifying USMCA trade is exempted

The United States amended the border order after two days. From March 7, goods that qualified for preferential treatment under the United States–Mexico–Canada Agreement were exempt. Non-qualifying Canadian goods remained subject to 25%; non-qualifying Canadian energy and potash were subject to 10%. This shifted the practical importance of origin documentation: a product made in Canada was not automatically exempt—it had to satisfy USMCA rules of origin and be entered accordingly. The amending order provides the legal detail.

March 12–13 — steel and aluminum open a second front

On March 12, separate national-security tariffs under Section 232 took effect at 25% on covered steel and aluminum imports, including imports from Canada. Unlike the revised border tariffs, these measures did not broadly exempt USMCA-originating metal. Canada responded on March 13 with 25% countertariffs on C$29.8 billion of U.S. imports: approximately C$12.6 billion in steel products, C$3 billion in aluminum products, and C$14.2 billion in other goods. This retaliation was separate from the March 4 list.

April–June 2025: autos and higher metals tariffs

April 3 and May 3 — automotive tariffs are phased in

A 25% Section 232 tariff began on imported passenger vehicles and light trucks on April 3, followed by covered auto parts on May 3. For USMCA-qualifying vehicles, importers could seek approval to apply the tariff only to the value of non-U.S. content. Qualifying auto parts initially received different treatment under the proclamation. The exact liability therefore depended on product classification, qualification, and content—not simply the country where final assembly occurred. The Federal Register proclamation is the controlling source.

April 9 — Canada retaliates on U.S. vehicles

Canada imposed a 25% surtax on non-USMCA-compliant vehicles imported from the United States and on the non-Canadian and non-Mexican content of qualifying U.S.-assembled vehicles. Ottawa also created remission pathways tied to continued Canadian production and investment. The current Canadian framework is described on the Department of Finance's automobile tariff page.

April 2 reciprocal-tariff announcement — no second blanket Canada rate

The administration's global reciprocal-tariff order did not stack a new countrywide reciprocal rate onto Canadian goods while the IEEPA border order applied. It preserved the March structure: qualifying USMCA goods were exempt, while non-qualifying goods generally faced the border rate. This is an important reason not to add headline tariff percentages together without checking the order's exclusions.

June 4 — steel and aluminum rates rise to 50%

The United States doubled the Section 232 steel and aluminum rate from 25% to 50% for covered products. Because Canada is a major U.S. supplier of both metals, the escalation was economically significant. Canada retained its own metal countertariffs while the governments negotiated.

July–November 2025: escalation, partial de-escalation, and trucks

August 1 — the border rate for non-USMCA Canadian goods rises to 35%

A July 31 amendment raised the IEEPA tariff on non-USMCA Canadian goods from 25% to 35%, effective August 1, and established a 40% transshipment rate for goods found to have been routed to evade the measure. Qualifying USMCA goods remained exempt. Canadian energy resources and potash retained the lower treatment specified in the order. The change was summarized in the White House July fact sheet.

September 1 — Canada removes most of its March countertariffs

Canada removed the countertariffs imposed on most U.S. consumer and industrial goods in March, citing the U.S. exemption for most USMCA-compliant trade. Canada did not remove its countertariffs on U.S. steel, aluminum, and automobiles. The Department of Finance maintains an authoritative current list. Canada's 2025 budget later reported that its countermeasures initially covered roughly C$95 billion in annual imports and about C$51.4 billion remained after the September removal.

November 1 — medium- and heavy-duty vehicles are added

A separate Section 232 regime imposed 25% duties on covered medium- and heavy-duty vehicles and parts and 10% on buses. For qualifying USMCA trucks, the 25% rate could be applied to non-U.S. content under the proclamation's certification process; non-qualifying vehicles generally faced the rate on full value. Again, the regime was product- and content-specific rather than a blanket Canada tariff.

February–July 2026: the legal foundation changes

February 20 — the Supreme Court rejects IEEPA tariff authority

In Learning Resources, Inc. v. Trump, the U.S. Supreme Court held that IEEPA did not authorize the President to impose tariffs. The same day, the President issued an order ending the additional ad valorem duties imposed under IEEPA, including the Canada border tariffs and the reciprocal-tariff program. The ruling did not terminate tariffs imposed under other statutes, such as Sections 232 or 301. Read the Supreme Court opinion and the implementing executive order.

February 24–July 24 — a temporary 10% surcharge

The administration then used Section 122 of the Trade Act of 1974 to impose a temporary 10% import surcharge for 150 days. USMCA-qualifying Canadian goods and products already subject to Section 232 were exempt. By law and by the proclamation's terms, the surcharge expired at 12:01 a.m. EDT on July 24, 2026, absent congressional action. It should not be shown as a current tariff after that date.

June 8 — metals rules are revised again

The United States revised its Section 232 regimes for steel, aluminum, copper, and derivative products. The framework contains several tiers depending on classification and metal content. For specified covered goods from Canada that qualify under USMCA, the additional 25% duty applies to non-U.S. content, with a minimum total effective duty of 15%. Broader 50%, 25%, and 15% tiers remain elsewhere in the regime. The June proclamation should be checked at the tariff-line level.

July 1 — the USMCA joint review does not produce a 16-year extension

The three governments completed the first six-year joint review without agreeing to extend the agreement for another 16 years. That did not terminate USMCA. The agreement remains in force, its present term runs to 2036, and annual reviews now continue under Article 34.7 unless the parties later agree to extend it. Origin qualification therefore remains central to current tariff exposure.

July 23–24 — Section 301 replaces the temporary baseline

USTR announced final Section 301 action following investigations concerning forced-labor import prohibitions. Canada was placed in the 10% group, but USMCA-compliant goods and specified products are exempt. The action succeeded the temporary Section 122 surcharge after July 24. USTR's final-action release explains the rates; Canada's official response confirms the USMCA exemption.

July 20 announcement — 50% Section 338 duties are prepared

The President signed three proclamations imposing additional 50% tariffs on specified Canadian products associated with motor vehicles, alcoholic beverages, and dairy. The proclamations said the duties would apply regardless of USMCA origin and were originally scheduled to begin at 12:01 a.m. EDT on August 19, 2026. They exclude energy, potash, Section 232 products, and certain products including fish and critical minerals. See the U.S. fact sheet and the initial Canadian response.

August 18–22, 2026: negotiations break down and a new tariff round begins

August 18 — Washington grants a short extension

After weeks of intensive negotiations, the United States postponed implementation of the Section 338 tariffs from August 19 until the end of August 21. Prime Minister Carney said the governments had made substantial progress but still had important work to complete. The extension was only a brief negotiating window, not a cancellation or long-term suspension of the tariffs. Canada's August 18 statement records the revised deadline.

August 21 — Canada suspends negotiations

The talks ended without an agreement. Prime Minister Carney said last-minute changes to the U.S. terms were unfair and uneconomic and called the reliability of a possible deal into question. Canada suspended the negotiations and recalled its negotiating team to Ottawa. This was a significant shift from more than a year of continued bargaining: the two governments moved from deadline-driven negotiation to renewed escalation.

According to the Prime Minister's August 21 statement, the new U.S. tariffs cover roughly C$28 billion of Canadian goods. That figure describes the estimated value of affected trade, not expected tariff revenue.

August 22 — the U.S. 50% duties take effect

When the extension expired, the additional 50% Section 338 duties took effect on the products covered by the three proclamations. Unlike the current Section 301 baseline, these Canada-specific duties apply to listed goods even when they qualify under USMCA. They are additional to ordinary duties but do not apply to products already subject to Section 232 or to the other excluded categories specified in the proclamations. The tariff therefore does not cover every Canadian export; exposure depends on the product's HTSUS classification and the annexes to the motor-vehicle, alcohol, and dairy proclamations.

August 25 — Canada publishes rate-for-rate countertariffs

Canada published the tariff-item list for its response and confirmed an effective time of 12:01 a.m. on September 8, 2026. The new countertariffs apply rates of 15%, 25%, or 50% to listed U.S.-origin products, with the rate for each product matching the corresponding U.S. measure. The government values the covered U.S. imports at C$27.6 billion and identifies affected sectors including steel, dairy, appliances, agricultural equipment, pulp and paper, and electronics.

The list is specific to tariff items and does not impose one rate on all U.S. goods. It excludes covered goods already in transit when the measures take effect, and the government said additional administrative details would be provided through Canada Border Services Agency customs notices. The controlling references are the Department of Finance tariff-item list and August 25 announcement.

Trade data: what the latest complete month shows

U.S. Census Bureau goods data for May 2026 show U.S. exports to Canada of approximately $29.8 billion and imports from Canada of $36.3 billion, a monthly U.S. goods deficit of about $6.5 billion. From January through May, exports were approximately $144.5 billion and imports $163.0 billion, a deficit of about $18.4 billion. These are nominal, not-seasonally-adjusted goods figures. They describe the relationship but do not, by themselves, prove that any single tariff caused the monthly movement. The underlying source is the Census Bureau's country trade workbook.

Current situation as of August 26, 2026

  • Ended: the 2025 IEEPA border tariffs, including the later 35% Canadian rate, ended on February 20, 2026 after the Supreme Court ruling.
  • Expired: the temporary 10% Section 122 surcharge expired on July 24, 2026.
  • In force: USMCA still provides preferential treatment when goods meet its origin and entry requirements. The new Section 301 baseline is 10% for covered Canadian goods, with USMCA-compliant goods and specified products exempt.
  • In force: product-specific Section 232 regimes continue for metals, automobiles, auto parts, medium- and heavy-duty vehicles, parts, and buses, subject to classification, origin, content, and exclusion rules.
  • Newly in force: after a three-day postponement, the additional 50% Section 338 duties took effect on August 22 for products listed in the three Canada-specific proclamations. USMCA origin does not exempt listed goods.
  • Canadian response: Canada's automobile countertariffs remain in place. The published September 8 list adjusts or adds rates for specified steel, aluminum, and other U.S.-origin products; most March 2025 consumer-goods retaliation was removed on September 1, 2025.
  • Published, not yet effective: Canada's tariff-item list is scheduled to take effect at 12:01 a.m. on September 8, 2026. Listed U.S.-origin goods carry matching rates of 15%, 25%, or 50%; goods already in transit on the effective date are excluded.
  • Negotiating track: Canada suspended bilateral trade negotiations on August 21. Separately, USMCA remains in force through 2036 under its current term, with annual reviews continuing after the parties did not agree to a 16-year extension in July 2026.

Bottom line: the August breakdown materially escalated the dispute, but there is still no single tariff rate for all Canada–U.S. trade. Current U.S. liability is a layered question: Does the good qualify under USMCA? Is it exempt from the Section 301 baseline? Is it covered by a Section 232 sector measure? Is it listed under one of the new 50% Section 338 proclamations? On the Canadian side, existing automobile countertariffs remain and the published September 8 list applies 15%, 25%, or 50% rates to specified U.S.-origin goods. Operational decisions should use current tariff schedules and customs guidance at the product-code level.