Is this Chinese takeover the new reality? Or, can a coordinated effort by the U.S. and its allies challenge China’s hegemony in the region? The Iran war and the fight for control of the Strait of Hormuz—through which vital oil cargo from Gulf countries feeds the global economy—is a reminder that America must not forget the South China Sea, another strategic region where China, a greater threat than Iran, has gained alarming control over many decades. The People’s Liberation Army (PLA) has blatantly seized key points in the region and built a fortified military presence by constructing artificial islands on...