Maybe we need an alliance with Vietnam. I don’t think that their people are hostile to us, only the leadership that wanted to run Vietnam for itself. Since we have no designs on them, and there’s no effective internal opposition - and a very credible outside threat - then Vietnam shouldn’t have any problems letting us back into Cam Ran Bay (for example). ‘Course, it’d make the Chinese hopping mad, but that’s kind of the idea.
Nice idea, but the reason the ChiComs pushed southward through Korea and Viet Nam was to prevent the West from having any foothold anywhere near China. That is why all of their actions, even this one, are calculated to intimidate the US from defending Taiwan, which is their keystone in securing incontestable dominance in their hemisphere.
ASEAN wants Uncle Sam to provide free policing for them while keeping their distance from him. The antidote for that is for Uncle Sam to stand by while China continues its encroachments on the ASEAN countries until they have no choice but to scream for help. At which point, we demolish all the structures China has built in the South China Sea, while forcing Taiwan to butt out of the area.