Section 338 Comes Off the Shelf

Somewhere in a customs brokerage this morning, an entry writer is looking at a shipment of Canadian auto parts and running math that did not exist a week ago. Fifty percent. Added to the commercial invoice value. Owed when the entry is filed.

The importer of record pays it. Ottawa does not. And the clock started ticking on July 20.

That is the reality behind a headline most people read as one more tariff story. It is not one more tariff story. It is the first time in its 96-year history that Section 338 of the Tariff Act of 1930 has been used to impose a duty. Let me explain what came off the shelf, and why the mechanism should matter more than the target.

// A power written for a different century

Section 338 lives at 19 U.S.C. § 1338. It is a piece of the Smoot-Hawley Tariff Act — the 1930 law most trade people know as a cautionary tale, not a toolbox.

The provision hands the President a specific weapon. When a foreign country discriminates against United States commerce — by charging our goods more than it charges everyone else’s, or by restricting our products in a way it does not restrict others’ — the President may impose additional duties of up to 50 percent ad valorem on that country’s goods.

Read the statute and you find a second gear most coverage skips. If the country maintains or increases its discrimination after the duties land, Section 338 lets the President exclude the offending products from entry into the United States entirely. Not a higher tariff. A door that closes.

The 50 percent is the first step. A full import ban is the second.

There is a fact-finding role in the law, too. Subsection (g) makes it the duty of the United States International Trade Commission, or USITC — the old Tariff Commission — to ascertain whether discrimination is occurring and to bring it to the President with recommendations. But the Commission finds facts. The President decides.

There is no mandatory investigation with statutory deadlines the way Section 301 of the Trade Act of 1974 requires. There is no Commerce Department national-security study the way Section 232 of the Trade Expansion Act of 1962 requires. That is the point. Section 338 is fast.

Fast, and largely untested. Franklin Roosevelt’s administration rattled the Section 338 saber at Germany, France, Spain, and Japan in the 1930s, then set it back down. The statute’s last known footprint was a 1949 State Department telegram from Secretary of State Dean Acheson — a reference, not a tariff. No duty was ever imposed under Section 338. After the General Agreement on Tariffs and Trade, or GATT, and later the World Trade Organization, or WTO, the provision looked incompatible with the rules the United States had helped write. So it sat on the shelf. Loaded, and never fired.

// Why now

The answer is a courtroom. In February 2026, the Supreme Court decided Learning Resources v. Trump and held, six to three, that the International Emergency Economic Powers Act, or IEEPA, does not authorize tariffs at all. That ruling took the administration’s primary tariff engine off the table. Section 338 is the replacement part.

On July 20, the President signed three separate proclamations under Section 338, each aimed at a different Canadian sector: motor vehicles, alcoholic beverages, and dairy. The stated grounds track the statute’s discrimination language.

Canada, the administration says, imposes tariffs and quotas on American automobiles that it does not impose on other countries’ cars.

All but two Canadian provinces halted the purchase, distribution, or sale of United States alcohol while leaving other nations’ products on the shelf.

Canada’s tariff-rate quotas on American cheese run far tighter than those it grants European producers.

The duties run 50 percent and reach a wide range of goods — everything from hockey sticks to cement, by the White House’s own description — with carve-outs for energy, potash, goods already covered under Section 232, and certain products such as fish and critical minerals. They take effect thirty days after signing. That is mid-August, not next year.

// The part the headlines miss

Here is what a practitioner needs to hold on to while the political coverage runs its course. The 50 percent does not land in Ottawa. It lands on the United States company named as importer of record on the entry.

That is the whole thesis of the trade I have worked in for twenty-five years, and it is the title of a book I just published.

Foreign countries don’t pay tariffs. You do.

When a Canadian auto-parts shipment clears in mid-August, the broker files the entry summary, and the additional duty is calculated on the entered value and owed to Customs and Border Protection, or CBP, by the importer. Not by the exporter. Not by the Canadian government. By the American business that bought the goods.

If your bill of materials runs through Ontario or Quebec, this is a line item on your next entry, and “wait and see” is not a plan for a line item.

// The defensive discipline that starts now

There is work that should begin before the effective date, not after the first entry liquidates.

• Know your true country of origin — not the country you ship from — because Section 338 duties turn on where goods originate.
• Confirm your Harmonized Tariff Schedule classifications on every Canadian-origin line, because the scope of these proclamations is defined by tariff number, and a wrong code cuts both ways.
• Model the landed cost at 50 percent, and decide what you do if the second gear engages and the goods are excluded outright.
• Document everything, because an untested statute invites challenge, and challenges reward the importer who keeps clean records.

// What comes next

Section 338 has no modern precedent, which means it has no modern settled meaning. Expect litigation. Expect complaints at the WTO. Expect Canadian retaliation aimed at American exporters. The same silence in the case law that makes the provision attractive to an executive in a hurry also makes it a target the moment the first entry is liquidated and the first importer sues.

Two futures sit on the table.

In one, Section 338 becomes the durable authority that replaces IEEPA and reshapes how tariffs get imposed for the rest of the decade. In the other, it follows IEEPA into the same judicial wall, and the importers who paid in the meantime spend years chasing refunds.

I do not know which one we get. Neither does anyone claiming certainty this week. What I know is that the shelf is empty now, the rifle is in someone’s hands, and the entries still have to be filed. Someone still has to pay. Make sure you know whether it is you.