The US is not really going to do anything. They won't even recognize Taiwan as a separate country. However, just dangling the idea that the US might side with Argentina on this could just be one more thing to remind the UK to behave like a true ally. The US will not forget the initial denial of access to Diego Garcia for attacking Iran and similar denial of access by other European allies, and their unwillingness to even send mine sweepers. Trump already sees the EU as the 2nd biggest threat to US dominance, even if its a military ally. However, if other NATO countries cannot be depended on to help in such situations, there really is not much incentive to play nice with them in the economic front. It is very clear that the other member countries need NATO more than the US.
I see the US more likely to consider Russia as an ally in the future against China and the EU. If US and Russia are allies, removing all US sanctions, Russia won't need China as much. Russia is not an economic threat to the US and in reality the two countries have no blood feud, unlike Russia and Germany for example. No nuclear powers are going to invade each other, so the real battles are fought by corporations for economic dominance. Imagine a scenario where the US is friendly with Russia, the middle east depend on US to keep peace among them, and the oil producing countries in the Americas aligned with the US... US becoming part of OPEC+... It will be OPEC+ vs. China and the EU.
en.mercopress.com
