“Unless Washington plans to wage a large-scale war in the South China Sea,” the nationalist-leaning Global Times warned, “any other approaches to prevent Chinese access to the islands will be foolish.”

For a country whose largest challenge is arguably in managing the expectations of its own people, such hawkish messages may be the more reliable sign.

Such escalations are likely to come in two varieties. Most obviously, Beijing could respond militarily. China could declare an “air defense identification zone,” or ADIZ, in the South China Sea, just as it did in the East China Sea in November 2013. This would effectively mean Beijing drawing lines in the air to mirror its claims in the South China Sea waters below.

More worryingly, China could begin building out more of the military infrastructure it has already installed in certain pockets of the South China Sea. China has already militarized one of its artificial islands (near the Spratly Islands chain), equipping it with weapons systems and military-grade landing strips. If they were to do likewise near the Scarborough Shoal — within striking distance of the Philippines and US military bases — this would almost certainly cross a red line for the United States.