Your question should be: what Vietnam must do to deter Chinese clowns?
- building up a conventional creditable defence force? Yes
- establishing a nuclear umbrella? Yes
- building a nuclear strike capacity? Yes
- seeking to be a part of a security architecture? Yes
- if all above can be provided by America, then be it.
Everything else is irrelevant. Chinese are the last people on this planet that can give us any advice on national security.
Do you think if you start a war against Vietnam tomorrow, you will ask us not to defend ourselves, nor allying with other major powers?
Do you think you can play a anti America card to make things as easy as possible for you?
America and Vietnam aren't historic enemies. The war happened by mistake, miscalculation.