Learning Resources v. Trump

That's the presidential authority to levy tariffs at their discretion.

There's a seminal case called Learning Resources v. Trump or v. the United States that's overturned that authority.

So presently, there still persists a tariff authority of the USA, but that tariff authority is diminished.

Now, I say this because under the Constitution of the United States, there is not a legal framework where somebody can levy a tariff on an exporter.