NATO works by projecting a united force. Nations unconditionally backing each other up. The USA is now clearly no longer a part of that. That's not to say that the USA will do nothing if a NATO member is attacked. It might. Or not.
This is because if Trump
Trump tore up Iran's "we won't do nukes" deal, doesn't matter whether you think they were genuine or not, it demonstrates we will go back on a deal so our word isn't worth anything.
Ukraine shows that the west will not actually protect you like they claim, so your only option is getting nukes to really deter people.
North Korea and Pakistan demonstrate that you can pretty much do whatever you want with just a couple nukes, the west will cower in fear over idle threats.
No country would look at any of this and conclude that they have any choice but to build nukes to protect themselves.
The main flow of capital in the US had been going to the mil.industry, but that is not the case anymore. It is mainly surveillance tech that is receiving capital. In a very unhealthy economy, this all looks eerily pre-'30s.
The US, right now, is only threatening weak countries, they don't have the industrial power to confront China, nor do they want it. This shouldn't be a surprise, some ideologues behind this maga-project belief in an America from one pole to the other. They believe in "spheres of influence", and as such China has their own sphere of influence. A sphere of influence means a kind of colony, where natural resources, people and industry are all resources to be extracted by them. It is the Russian model, it is the model of criminal mobs, it is might makes right, it is a multi-polar world.
Meanwhile, re-industrialization projects have been scrapped, partners have been scared of, and tariffs have hit the industry that was still left in America.
Monopolists are parasites on the economy, and the US is already very weakened from that. As the Japanese said, the US is still a great power, but the throne is empty. I suspect there will be skirmishes with other "great powers" over exploitable resources like Africa, Middle East, Europe, but I don't expect the current crop to go all-in on China.
No longer committing to defend other NATO countries, even if their military spending exceeds the target, is abandoning the alliance though. NATO is little else than that commitment.