Canberra confirmed last week that the Australian Navy won’t conduct freedom-of-navigation patrols in the international waters of the South China Sea, giving China’s bid to dominate the strategic area a boost. Such patrols are a basic requirement for the rules-based global order that Australia says it is committed to upholding.

An international tribunal ruled in July that China’s bid to claim most of the sea violates international law. But the verdict will be rendered moot unless law-abiding states are willing to push back....