UNCLOS has ruled on China's claim to the South China Sea and China is totally on board with it. Just kidding! Now the fun begins.
The Philippines sued China about its territorial claims in the South China Sea and won--basically, the UN said that China's claims to the territory are total BS because the rocks in the South China Sea aren't real islands.
China has (not surprisingly) said that they're not going to follow the judgment (despite being a cosigner of UNCLOS). Now there's a bit of a crisis: how can the world enforce the ruling? Sanctions? Military?
And what happens if major world powers begin openly flouting international law? What happens to those institutions and international world stability? It's a scary thought.