At 12:01 a.m. Eastern on Saturday, August 22, 2026, the United States began collecting an additional 50 percent duty on specified products of Canada - the first time a president has used Section 338 of the Tariff Act of 1930 to impose tariffs. The legal findings name dairy, alcohol, and motor vehicles. The customs lists run much wider: hundreds of tariff lines, about $20 billion a year, and no exemption for USMCA-origin goods.

This short professional briefing explains the statute, the three July 20 proclamations and the August 18 three-day delay, CBP filing headings, what is excluded (energy, potash, Section 232 goods, and others), why USMCA origin does not help, and Prime Minister Mark Carney's announced dollar-for-dollar Canadian retaliation effective September 8. It uses only sourced figures and on-record remarks from the White House, AP, Reuters, CNBC, CSIS, and the Chicago Fed. It states plainly what is still unknown: Canada's full product list, any court test of Section 338, and the price pass-through no official agency has measured.

Written as a digital-only nonfiction brief for importers, reporters, and readers who want the machine - not the slogans.