I Notice The U.S. Military was smart to claim Islands other than setting it up in South Korea and Tiawan
Now if they did set them up inside those nations. the chances are will leave the U.S 2 Options. either South Korea will give the U.S a signal to attack any Chinese Ships that would lead to China and North Korea to attack South Korea. That would be an Easy Green Light for them.
or the second Option. wait which won't do any good either. that would give China more time to prepare to build up their surroundings for Security and their Offense.
The best way for the U.S that can freely do whatever they want... claim Islands