We're searching for mines and underwater construction. They know we're searching for mines and underwater construction. We know they know we're searching for mines and underwater construction. It's the dance we used to perform with "Russian fishing trawlers" - the CIA has a whole bunch of boats that are ostensibly civilian, and the navy does a bunch of research and cataloguing that's ostensibly peaceful. Everybody on both sides knows that it's quasi-military feinting and every now and then one side or the other slaps someone else's hand. This is the way of open-water diplomacy. This happened back in 2001 for many of the same reasons - China testing to see what the new administration will do in the South China Sea. They figured Bush was a cowboy with no ideas about foreign policy and the US response to the incident helped shape relations for eight years. I think we flunked this one. Unpresidented indeed.