Like GP said - America's enemies.

Ah, light bulb slowly going on. I was thinking Russia, North Korea or China. The traditional enemies.

Is Trump not their US representative in chief?

I agree on Russia, but wouldn't be so sure Trump isn't a Russian asset.

That's an over-simplified answer. There are many people who share in the blame. Him for doing it as a visible catalyst, everyone who voted for him, presidential advisers who recommended these disastrous policies, and those who sat idly by and let the country be destroyed without acting to prevent it, especially those with greater-than-ordinary power who failed to act.

The buck stops here - Harry S Truman. He had this sign on his desk when he was president.

Here is an explanation of what it means:

https://www.trumanlibrary.gov/education/trivia/buck-stops-he...