That was stupid but also practically irrelevant-if an uninhabited territory has zero exports, you can set the tariff as high as you like, with no exports nobody is going to pay it. To be clear, I don’t agree with these tariffs and think they are a mistake, but I think we should focus on their real world harms not a silly administrative error
We know how it happened: Heard and McDonald Islands is an uninhabited Australian territory off the coast of Antarctica. In the 19th century, it was inhabited by sealers for an extended period (mostly Americans, some Australians too)-but they left after hunting the seals to extinction. In the 20th century it became a nature reserve, although it saw multi-year occupation by scientific research bases. Since the 1990s, no humans have been there except for brief visits; apparently nobody has been there in person for over a decade. It is illegal to come ashore without permission from the Australian government, and their policy is to almost always refuse permission (with rare exceptions for scientific research).
Yet despite all this, ISO 3166-1 gave it a country code, HM. And US government databases ended up showing imports from it, almost certainly due to data entry errors, the imports having really come from somewhere else. But it appears nobody was paying attention, so it ended up as a tiny trade deficit in official US trade statistics. And then the Trump administration mindlessly applied the rule “IF official US trade statistics show a deficit THEN impose tariff”. And still nobody noticed. And then after they publicised it, somebody did, and they were widely mocked for the mistake, and I believe this specific tariff has since been rescinded.
Most likely HM was actually a typo for Hong Kong (HK) or Honduras (HN)-adjacent keys on the keyboard. Or maybe the M is correct and the H is the typo, in which case it could easily have been The Gambia (GM) or Bermuda (BM) or Jamaica (JM)-also adjacent keys
Australia has another uninhabited territory (Ashmore and Cartier Islands), and another near uninhabited (Coral Sea Islands, staffed by a tiny rotating crew of government employees)-but, for whatever reason, ISO never gave either its own country code, [0] so this couldn’t have happened to them. (Likewise, Australia claims a big chunk of Antarctica, a claim which most countries-US included-don’t recognise-so the Australian Antarctic Territory doesn’t get its own ISO code, it gets subsumed under Antarctica’s, AQ.)
[0] I guess the reason may be land area - Ashmore and Cartier Islands have a land area of slightly over a square kilometre, less than a square mile; Coral Sea Islands have a land area of 3 km^2, which is slightly over one square mile; by contrast, Heard Island is 368 km^2 (142 sq mi). ISO generally resists giving codes to uninhabited territories unless they contain significant land