Trump threatens Mexico and Canada

Donald Trump threatened on 25 November to put a twenty-five per cent tariff on all imports from Mexico and Canada on his first day in office, tying it to border enforcement and drug trafficking. The threat went straight at the USMCA free trade agreement that binds the three economies together.

A threat with a history

The announcement, posted on social media alongside a pledge of an extra 10 per cent tariff on Chinese goods, named fentanyl and illegal migration as the grievances and said the duties would stay until both stopped. Mr Trump has used the tactic before. In May 2019 he threatened escalating tariffs on all Mexican imports unless Mexico curbed migration, and dropped the plan about a week later when Mexico agreed to send its National Guard to its southern border. In 2018 he imposed steel and aluminium tariffs on both neighbours, which retaliated against American goods until the duties were lifted in May 2019.

The scale is large. Mexico and Canada each sell the United States more than $400 billion of goods a year, and each buys a large share of America's exports in return. Together they account for more than a quarter of all American goods imports, and a tariff on both would reach far more trade than all the duties on China imposed since 2018. Much of that trade takes place inside what is, for many industries, a single production system.

Parts that cross borders

Trade with China is mostly in finished goods. Trade across North America runs through shared supply chains, especially in cars, energy and farming, where components cross the border several times before final assembly. A twenty-five per cent tariff on Canada and Mexico would halt car assembly lines and push up petrol prices in the Midwest. Margins at companies across the continent would take a hit.

The legal route is already mapped. In 2019 the threat against Mexico relied on emergency economic powers, which allow the president to regulate imports after declaring a national emergency, without a vote in Congress. Tying the tariff to fentanyl and migration fits that template. It also means the duties could be imposed on the first day, as promised, and lifted just as quickly if the neighbours offer concessions.

How the cost would spread

The car industry shows the mechanism most clearly. A part cast in one country may be machined in another and fitted in a third, and a duty charged at each crossing compounds as it moves along the chain. Carmakers and their suppliers run lean inventories under just-in-time production, which is why a border tax would reach assembly lines within weeks rather than quarters. Energy follows a different route: Canada is the largest foreign supplier of crude oil to the United States, and many Midwestern refineries are set up to run its heavy grades, so they cannot easily switch to other sources.

Retaliation would travel the other way. Mexico is the biggest foreign buyer of American corn, and in 2018 both neighbours aimed their counter-tariffs at farm goods and at products made in politically sensitive states. Agriculture would again be the obvious target, leaving American farmers to pay for a dispute about borders and drugs.

The USMCA was designed to lock that system in. Its rules of origin require a car to contain 75 per cent North American content to cross borders duty-free, which pushed carmakers to source more parts within the region. A tariff on all Mexican and Canadian goods would penalise the very firms that complied. Shares in General Motors, which builds many of its pickups and sport-utility vehicles in Mexico, fell sharply after the announcement.

Food prices would feel it too. Mexico supplies most of the avocados and much of the fresh produce sold in American supermarkets in winter, and Canada provides most of the potash that American farmers use as fertiliser. A tariff on those goods would feed quickly into grocery bills and farm costs, with little prospect of domestic substitutes on a short timescale.

Mexico's awkward position

The timing is poor for Mexico. It overtook China last year as the largest source of American goods imports, partly because companies moved production there to escape the tariffs of the first Trump term. Those investments were made on the assumption that access under the USMCA was secure. A blanket tariff on Mexican goods would punish the very nearshoring that Washington had encouraged as a way to depend less on China.

Canada faces a different problem. Its economy depends even more heavily on the American market, and a large share of its exports is energy, which a tariff would make more expensive for American refiners and drivers. Ottawa has fewer levers than Mexico over migration and drugs, since far less of either crosses the northern border. That leaves it with the unappealing choice between concessions on unrelated issues and retaliation against a much larger partner.

Bargaining chip or policy

The strongest counterargument is that the threat is an opening bid. The 2019 episode ended in a deal within days, and the USMCA, which took effect in July 2020, has a joint review due in 2026 that gives Washington a formal forum for leverage without tearing up the agreement. The peso and the Canadian dollar both fell after the announcement, a sign that markets are taking the threat seriously even if they doubt it will be carried out in full. Even as a bluff, a threat repeated often enough changes where companies choose to invest before any duty is paid.

The indicators to watch are the retaliation lists drawn up in Ottawa and Mexico City, any concessions on border policing, and whether the threat reappears in an executive order after the inauguration on 20 January. A signed order would move the argument from rhetoric to customs receipts.

If Trump follows through, Detroit and its suppliers will feel it first, within weeks. The threat alone puts America's closest trading ties at risk and hands both neighbours a reason to retaliate. Expect the peso and the Canadian dollar to stay under pressure until the inauguration, and carmakers to delay investment decisions in Mexico until the threat is resolved.