If you're worn out worrying about Syria, Gaza, Iran, you name it, I give you: the announcement today by police on China's large southern island of Hainan that, starting on January 1, they will assert a right to stop and board any vessel they consider to have violated China's very expansive claim of territorial waters in the South China Sea.
Take a look at this rendering of the area over which China asserts territorial sovereignty. More details below, but the red line encloses what China considers its own sovereign area; the blue shows Vietnam's claims; the purple shows those of the Philippines; the yellow is Malaysia's; and the green is from Brunei.
Now let's add the detail that the faint white lines on the map show major shipping routes -- whose importance is even greater than the map suggests. Obviously lots of commerce in and out of China goes through Hong Kong and neighboring ports. But shipping lanes that have nothing directly to do with mainland China, including the export paths from Japan, South Korea, and Taiwan to Europe, pass through these waters toward the Indian Ocean. Half the world's oil-cargo traffic comes back the opposite way, from the Middle East, through this same route.
For months, Chinese patrol boats and other craft have scuffled with foreign vessels, mainly from the Philippines and most often over contested fishing grounds. But an assertion from officials in Hainan that they can stop and board any vessel passing through these waters is something quite different. The US Navy has had a lot of different missions over the centuries, but one of its elemental purposes has been defending freedom-of-navigation on the high seas. The Seventh Fleet is the regnant military power in this area. I am usually in the "oh calm down" camp about frictions, especially military, between China and America. But it is easy to imagine things becoming dangerous, quickly, if the new Chinese administration actually tries to carry out this order.
Let's hope the Hainan diktat will just go away, or will not be enforced, or will be dismissed in Beijing as some oddball over-reach by authorities in the far south. A Chinese government deliberately courting this kind of showdown would be a very bad sign.
More on South China Sea disputes; the origins of the Chinese claims, often referred to (for reasons you'll see) as the "nine-dashed line"; other tensions involving the nine dashes (plus this); initial US reaction.