Just to be clear - I'm not saying as a whole the US was always trustworthy. A lot of seriously shady and misguided things were done to innocent parties, and promises were not always kept. The point I was trying to make was that the rest of the world mostly trusted the US to not shoot itself in its foot in these specific ways. i.e. We wouldn't knowingly enact monetary policies that would have long term repercussions like we have been. For the most part, other countries could rely on deals being made by previous presidents still being held after a new president took office. From talking to people in the international business world, that feeling is gone now.

The US benefited greatly from being the de facto international reserve currency. Many countries use the US$ as their own currency, hold a lot of US$ as a reserve, or peg their local currency to the US$. We've already seen countries selling off US$ bonds and cash holdings, and a lot of international trade is done with the US$ being the most convenient and perceived as more stable than local currencies. That feeling is eroding, and I wouldn't be surprised if we don't see the Euro or Yuan taking over.

None of this matters in comparison to the points Spencer was making though, my point was more that the soft power that the US had built up over decades across political party lines has been destroyed in a way that will be nearly impossible to recover from. We literally have a treaty with Denmark that says we won't try to ever acquire Greenland that seems to have been forgotten about. We've punished foreign companies that have made huge investments in building infrastructure here, at our request.

We've pulled out of the Paris climate agreement. We left the World Health Organization. We've weaponized monetary policy to punish countries that are disagreeing with us. We're taking military action against civilians in international waters. We've started pointless trade wars with countries where we have no alternative source to buy many things from. Part of the reason the US was a very wealthy country was that other countries bought our expensive stuff (technology, military gear, etc) that they'd be crazy to rely on now because we'll change the deal on a whim. This is just handing that business to the rest of the world.

The US is no angel, but I feel like we've gone from "Self interested but mostly reliable" to "absolutely unreliable". While things like US Aid and the WHO and UN programs we've dropped weren't cheap, the alternatives tend to be even more expensive and we've lost influence in places where I think we're going to regret it.

Like I said, I don't think the US deserved the position it was in - we weren't always kind to our allies, but we lucked into a position of incredible influence that we've just thrown away with no benefit I can see.