Each terrains presented different challenge in it environment. There no place for US ships to hide in the East China Sea, US Navy still need to deploy into Taiwan strait to confront the China navy, US aircrafts launchsite on the US base are well within the reach of China attack from the air, space, Sea, deep sea. Those US forward base won't be safe when China underattack, Taiwan action have the implication that will lead to WW3, tell me will the US risk a WW3 over Taiwan independent aspiration by Taiwan president ambition for reelection to play the independent card for votes? Not a single US population willing to die on behalf of Taiwan. Vietnam war caused of US retreat because of a merely 40 to 50 thousands of US soldiers died and hundreds of billions dollars wasted that weren't in the best interest for the US to continue to fought that war. No population willing to die for an unpopular war.