Trump can close down a lot of the British NHS by telling AWS to stop supplying it. Everyone apart from a few countries (China, Russia, Iran, North Korea, etc.) is dependent on the US.

Yes but that’s a blunt instrument, which would risk reaction. However putting an individual on a sanctions list is routine and easy.

And a president could always just call up the CEOs and ask for their least favourite Norwegian to be cancelled without any paperwork.

As happened to ICC judges and prosecutors.