Not really explained. Idk.
Everything is very complex and multi-layered. No one can explain it. But I'll give one angle that might be true.
First of all..
Have to step back from the idea that Donald Trump or any US President has a lot of power and is organically creating the agenda.
Whether it's shadow government Illuminati banking overlord type of stuff, or just what the public collectively feels and wants, the President seems mostly like an actor to me. Managing and being the spokesperson more than he's controlling the tide.
2nd...
The Chinese economy seems clearly in motion to pass the US economy and eventually be the world powerhouse.
(At least, right now that seems true. Who knows if 10 years from now money doesn't matter and the robots deliver everything, and the air is a little cleaner over here, so here is better. You never know.)
Democracy is really a mess. People glorify it as some sort of ideal. What's ideal is that Western democracies happened to also have a high regard for personal freedoms (freedom of speech, freedom of press, freedom of association), and for limited intervention in the market.
So they flourished. (Because of those ideals and tendencies, not because democracy was the way decisions got made.)
But China patiently lurked. They learned that free economic activity is the mechanism to production and wealth. (Or maybe they already knew it, but they saw that now the whole world was learning it and they'd have to go in that direction to keep up.)
In a democracy, the people who steer the ship are politicians who generally only care about what works best for themselves rather than the overall viability of the system. And so decisions will always be with a short-term focus of whatever works in the moment, or even gives the appearance of working in the moment, rather than what's actually best long-term. Whereas in China, everything can be constantly measured for the long-term and for what actually works.
China is like the old man with the cane, viewing watching and maneuvering in a calculated way. The teenager might have some slick moves, but the old man knows all the angles.
Aside: A decentralized, lack of anyone trying to rule over others would be the best and produce the most wealth. But as long as there are rulers and centralized bodies like this, China's system is more crisp and long-term oriented than a democracy.
So where people will typically think of secret government CIA operative overlord bosses as a bad thing, I actually hope that's how it works. I hope it's like 5 people who secretly run the US. Because that's actually better than democracy and politicians being the source of how decisions get made.
(The 5 people at least have a shot and might be great at it, whereas democracy is inevitably bound to suck and unravel.)
Anyways, I digress..
So here you have the tipping point..
Where the US is still thought of as the top gun, and China is rising.
Right now, the trade war seems to hurt China a little more than it hurts the US. (Whether it should be perceived that way etc is a different question, and it probably shouldn't be. But Chinese markets seem to have gone down more than US markets.)
The US is the more mature market with perception, especially in a time of stress and uncertainly, more likely to favor it and see it as the safe move.
So I see this as like a late empire "delay" to China's rise.
Amping up the uncertainty is more bad for China (in the short-term) than for the US in the short-term.
Long-term it's likely the other way around.
Maybe there's some secret high level reason why it somehow helps the US to delay China-- maybe there's a known risk of how they would behave militarily, and the longer you can delay it, it gets cheaper and easier to have sophisticated defense and anti-missile type of technology. And so then there's some actual purpose to wanting to delay their rise.
(After you centralize everything and everyone fights with each other, it's hard to know what all is going on and what the decisions are based off of.)
But just looking at it from what we know, it seems certainly more bad for the US long-term. China, at least, has a structurally sounder economy and billions of people or whatever.
The US is more just running on fumes and perception right now.
Tho I'm hopeful for a big awakening and explosion of American wit, whenever all the damage of the past 80 years or whatever washes away.
Freedom works, and maybe we'll rekindle with that in a deeper and principled way and help drive the next wave towards a truly free and decentralized, non-violent world.
But ya, that's it-- Maybe the "point" is to delay China's ascent. Like if someone is passing you in a race, dragging each other down is more fine with you than it is with them.
Whether or not it makes sense, maybe that's just how an empire is installed to behave.
Idk.