What brought this decision on from the Hermit Kingdom?
Well, the fact that he was scared to death of getting nuked by Trump and Biden has made America look impotent and toothless, has a lot to do with it.
It's cute how you refer to anything not following China's orders as a "US Vassal State" though. You know, here's a hint. Goebbels Tactics work better when they're believable.