> but you can't even apply “tariff” to movies as it is IP, not physical goods (on which tariffs apply
A government can apply tariffs to any exchange it chooses, but movies are explicitly excluded from the law on which Trump has relied for tariffs, so short of getting a new law passed to authorize movie tariffs, there is no legal authority.
> A government can apply tariffs to any exchange it chooses
My point is that it can apply taxes equivalent to tariffs (well, like you said, only Congress can), but since it's not going to be defined by the same law or be regulated by the same international conventions and isn't going to be collected by the same administration nor from the same people (the tax will be raised on the retailer directly, unlike tariffs), I think it's fair not to call that “tariffs” since it's really going to be a very different type of tax.
A government can apply tariffs to any exchange it chooses, but movies are explicitly excluded from the law on which Trump has relied for tariffs, so short of getting a new law passed to authorize movie tariffs, there is no legal authority.