[thaumasiotes]

So, they need to argue that the foreign countries' practice imposes a disadvantage in fact on the commerce of the USA compared with the commerce of any foreign country? They already have argued that; it was headlined in Trump's first announcements.

[tptacek]

Any business impacted by the tariffs will have standing to go to federal court and argue that trade practices accepted for a century by legislatures and administrations of both parties do not constitute "unequal impositions" under the intended meaning of the statute.

[thaumasiotes]

They'd have to argue something other than that. There could be a standing regulation that says "Ships carrying any American goods must pay 30% higher docking fees"; if that had been accepted for a century, it would still be a slam dunk case of "unequal impositions".