Who loses if China controls the South China Sea?

Who has the most to lose if China controls the South China Sea?

Many states do: the trade route matters widely, and a successful artificial-island claim would create a dangerous maritime-law precedent.

Japan, India, Vietnam, the United Kingdom, and the United States all have something to lose because the South China Sea route matters to trade. Control would affect states far beyond the immediate claimants because ships that cannot use the route must accept added risk or distance. The legal precedent is equally important: a state could turn a claimed reef into an island and then claim a broad exclusive economic zone around it. Accepting such a rule could later allow another power to use the same technique against China.