[BirAdam]

For the USA, war (at some level) has pretty much always been constant. Autarky also isn't new to the USA. The current on-shoring movement seems to me to be more about the USA's empire collapsing, and the military contractors getting worried about their supply lines. So, prelude to WWIII? Maybe, but it can be explained in other ways.

[TulliusCicero]

To the extent that the US has an empire, it's not collapsing right now. The US continues to maintain plenty of foreign military bases, US military alliances and partnerships are strong (arguably NATO is now stronger than it was in the recent past), and overseas territories like Guam are still firmly under US control.

What's changed is that China continues to rise in power and exert its influence, combined with Russia's invasion of Ukraine making the West antsy about dependencies on China as well as Taiwan (if China invades or blockades Taiwan).