I can never understand that country, Vietnam for seemingly siding with the U.S. and it's population being more susceptible and having a more positive attitude towards the U.S. a country that they fought tooth and nail to gain independence first from France and then from the neo-colonialist America. Vietnam was the most bombed country in the 20th century having bombed by the American military exceeded what was dropped in all of WWII; killed more than a million civilians and the hundreds and thousands more becoming refugee and yet the country and it's people seems to hold more grudges against China because of their border war in 1979?
The P.R.C. should have just annexed more lands and Vietnamese territories if it had known that Vietnam with an almost identical political system is going to be this pathetic, hostile towards China and servile towards America and it's regional interest.
Traditionally, there is a saying..."Vietnam has an affinity to whoever can provide mother's milk."
Vietnam, like Japan, has traditionally allied with the most wealthy and powerful nation in the world order, whether it was Imperial China in antiquity, British empire in WW1 (French in Vietnam's case), Nazi Germany in WW2, and Americans in the post-WW2 era (Soviet in Vietnam's case).
Once China becomes the most wealthy and powerful nation, both Vietnam and Japan will compete to lick China's bumhole, much like antiquity.
In otherwords, these nations only respect wealth and power.