Looks like the South China Sea issue has now been internationalised, with the US' and Chinese military forces eyeballing each other...
Exclusive: China warns U.S. surveillance plane
I wonder if the Philippines and Vietnam -- two of the claimant states, and the two that have most frequently crossed swords with China over the South China Sea -- are now happier with the new development.
Meanwhile, Japan has a dispute with China over their rival claims in the East China Sea. That's another area where China can ratchet up pressure on a US treaty ally.
On the other hand, the last thing China wants is to be perceived as a common military threat to both Northeast and Southeast Asian countries (and to Australasia as well).