It does not seem illegal to me--------but I am not all that sure about
BUILDING ISLANDS in international waters
It creates an interesting international legal issue
If I build my own island in the middle of international waters, do I get to stake out a 12 mile radius of ocean around it?
Ahh nope....
China, like Russia is pushing every button it can to antagonize the US.
Their ( wrong) thinking is that due to economic issues, trade mainly, this administration will sit idly by while China becomes increasingly belligerent.
I guess the Chinese think we will not do anything because US and China trade is vital.
If it were up to me, I'd tell the Chinese that "things" can go wrong at any time. The world is an imperfect place.
Then go hire some these little punk ass hackers to attack China on line. LOL