The US is a powerful country. Which means it has a lot of impact. If that impact also tilts towards the negative spectrum then they will have a large negative impact. Certainly a bigger impact than North Korea, even though North Korea is worse to live under. (Side-note: but America also exports suffering, so it’s not just about US citizens.)

Chomsky: Today's Republican Party is a Candidate for Most Dangerous Organization in Human History (2016) https://www.youtube.com/watch?v=4FC7PsvUjo8