Dear Andrei,
Vietnam was forced to the point of no choice.
1. During 1945, we are so poor that Soviet Union even doesn't care about our idea, althought president Ho Chi Minh get his inspiration from Lenin. We find the moral support of the Alliance, especially USA ... they support us at initial but change their mind to support KMT, because they doubt that president Ho Chi Minh is communism.
President HCM ever sent many letter to President Harry Truman in hope getting the same level of support as Phillipines but get no positive response. This would be a regret for both, USA and Vietnam.
2. Since 1950, Soviet Union paid more attention to Vietnam and really full support to us. Thanks for the love of Russian to Vietnam.
At the time, Vietnam must learn first lesson of existing among China and Soviet Union ... China is always trying to isolate us from Soviet Union in the past... or from USA, Japan by now.
Vietnam has no choice to be neighbor of China who is no doubt always pursuing to invade Vietnam and snatch from Vietnam hands even smallest resource, like fish in SCS,
As a matter of fact, there's no neighbor sharing the same border with China getting rich.
3. For Sino-Vietnam war 1978-1979, what can we do not to be invaded by joint-attacked forces from Cambodia and China. If we want not to let them divide our country, we must counter-strike.
The invasions leave us no choice but fight back.
4. Nowaday For conflicts in SCS, we also never accept there is a giant country draw the line that whole world laught at and apply it to us. We never shoot a bullet to them, ask for meeting ... all we want is respect the international law, not any unilatery act applied.
For example, residents of Ly Son (pop 30,000 ) islands , Vietnam are very surprised to hear the sea water area they always reach after few hours of sailing for centuries without meeting any Chinese, was in a historic zone of Chinese just created within recent few decades.
Same to Phillipines fishermen one day head for Scarborough shoal and found the banner "this is the undisputable territory of China since 2000 years ago". Same to Malaysian with Jame Shoal, Indonesia with Natuna Island, Japan with Senkaku ...
We, small countries were pushed to the point of no choice like that ...
If we have another better choice, why we must confront to China ?
I realized all other countries not only Vietnam paid more on military equipments, Pinoys, Japanese, Malaysian, Indonesian, Vietnam, India ... is there any other enemy they worry about but China?