Here's White House spokesman Sean Spicer today when asked about how the U.S. would deal with Chinese claims in the South China Sea:
Areas in the South China Sea that are part of international waters and international territories, I think the U.S. is going to make sure we protect our interests there. So, it's a question of if those islands are in fact in international waters and not part of China proper than yeah we're going to make sure that we defend international territories from being taken over by one country.
Why this matters: New York Times columnist Nicholas Kristof:
For more details on the issue see the Axios Facts Matter on the South China Sea.