For the most part, they are allowed to try that, right? And, most large economies are able to transact in whatever currency they want.

It does seem different, since America has no mechanism for setting other nations' tax and regulatory policies.

That said, I think fairness is pretty dumb in situations like this. The relevant criteria is what's best for people. Just because other countries are doing dumb stuff to their economies, doesn't mean we should follow suit.

America overall pays more for imports and this pushes the allocation of capital to inherently inefficient US based manufacturing. America loses overall with increased costs and mis-allocation of capital on a massive scale. The US government enjoys a windfall of revenue, paid for by consumers and businesses who pay more for the goods and services they want or need. USA becomes less competitive as other nations are not hit by these additional costs and large scale mis-allocation of capital.

This is Trump admitting that USA has lost the trade war and so he wants to rig the game. It might buy time but its not going to fix the underlying problem. US economy and empire is corrupt, inefficient, obese, burdened by too many rentseeking clingons and so in structural decline. Global fiat monetary hegemony created an addict that is beyond recovery.