That is difficult and complex. The U.S. has diplomatically agreed to the one China policy, which undermines Taiwan’s ability to make treaties and allegiances. It has also complicated Taiwan’s inclusion in international bodies and agreements. The U.S. has also stated they would assist in the defense of Taiwan if China tried to force unification, which is in direct conflict with their claimed support for the one China policy.

So now telling Taiwan to not declare independence is just another scoop of BS on top of the shit cake the US has been creating for decades with their two-faced spineless tightrope walk between China and Taiwan. And all of the diplomatic garbage has had the end goal of trying to gain an upper hand in order to exploit the two nations. Now that China has grown in diplomatic, political, and military power the U.S. can do little to exploit them and is trying to find a way to still wield influence in the region.

Trump is too stupid to even understand any of that however. So he will flail wildly and likely the world as a whole will be worse off for his fumbling ineptitude when it comes to his weilding U.S. hard and soft power.

So what the U.S. should do is probably stop letting Trump be in any kind of office. Stop trying to exploit nations for its own enrichment. And stop being a spineless pile of shit and take a stance. Either stand by and support allies, or stop claiming to be an ally. But that will never happen.