As has been pointed out, Trump is like the hammer that sees all problems as nails. In Trump’s case, all problems can be solved by a wall. Of course, you have to put the wall in the right place, since the majority of cases in the US originated in Europe, with the UK have the 2nd largest share.

The irony in Trump’s Wall solution is not only it was the wrong wall, it was that the guy in his cabinet that has been his chief advisor on all things China was ignored for another month after taking his advice on the travel ban: In January Peter Navarro was practically screaming at Trump that COVID was a pandemic likely to infect 100mm Americans and kill 1–2 million. And Trump and Fox News said “no big deal, we got this”. Even Steve Bannon was flipping out over Trump’s ignoring the situation. Not because, however, they cared about people’s lives. Nope, that is not theirs or Trumps things. They were worried most about the political side effects.

As for the WHO, the US has a very direct interest in its effectiveness, which has been systematically undermined along with other UN agencies. A “pandemic” means it is every where. Now, if you would like to see Russia and China run things in the rest of the world or have the most influence, then you and Trump are getting it done.