We don’t need a shooting war and the majority of Americans are against. Keep putting tariffs on China and make them howl. A war would bankrupt them.
If it’s a shooting war you want send a couple of MOABs into the Three Gorges Dam. Mother Nature and The Yangtze River will do the rest.
If doesn’t necessarily have to be a shooting war, just a strategically placed series of bases and the ability to use it to exert influence. Of course, today America has the technological advantage to force it’s way into the South China Sea regardless of Chinese bases but that wont necessarily be the case in 20-30 years time when China closes the gap but the bases they have established now will be used to basically deny the US ability to open the South China Sea to trade if China decides to close it.