I'm a Vietnamese with Nghe An root, so pardon me if I'm a little surprised at this statement.
Has the world learn nothing from history? This is not my question, this is a question that was asked countless times by politicians and scholars during the Vietnam/American War.
China had tried to invade/colonize Vietnam for over 1000 years, and each time, they went home in shame. Mongolians, Manchurians were able to take over the entire China, yet weren't able to completely dominate or wipe the Vietnamese people out. Vietnam is a VERY small country comparing to China and I think wars aren't always decided by military strength.
Unfortunately, like many other smaller countries, Vietnam doesn't have a China problem, it currently has a Vietnam problem. China keeps pushing and the smaller countries are going to realize that they can't fight a bully by themselves. For Vietnam, China keeps pushing, it will expose the Sino-friendly elements of the Vietnamese government and will escalate a change in government power.
So perhaps "China can do pretty much whatever it wants"... for a short time. Because if the water is under so much pressure, it will break the dam.