One day in his tweets he is all praise for China, as a good and sharp negotiator, and in another vein accuses it as dubious conspirator against US in collusion with Russia and No. Korea. And this, he does with most anybody he deals with, all coming out from both sides of the mouth. Very friendly and congenial, yet at the same time quite stinging in his derogatory assessment of the same personality or country.
And the world is confused. Not understanding why he does this, amid the plethora of statements he throws around each day whenever he can.
Trump understands the utter interdependency that countries in the world have with each other. This time, no country is an island. One may be a gigantic exporter of goods, but without the buyer of those goods, it cannot prosper or even survive. No country can survive with its own exports. It has to convert them to liquid assets/funds so they can be converted either to imports or assets to be used for sustaining its own economy.
True also between countries who are debtors and creditors. The US for example has floated billions of its treasury debt instruments and are accepted and preferred globally, and some countries hold considerable amounts in their portfolios. And yes, some have threatened to destroy the US with them. But do what? It would be like cutting your nose to spite the face.
So no country is only either an ally, or simply an enemy. Each one could be partner to the other. That dreaded idea of co-existence during the Cold War should be relevant again.