United States Defense Secretary Ash Carter warned a few months back that China risked a "great wall of self-isolation" for its actions in the disputed South China Sea. That hasn't deterred President Xi Jinping.
Beijing is boosting its military presence in the area unabated in the face of stepped-up U.S. patrols and following a recent arbitration court's ruling that invalidated its claims to most of the waterway.
After decades of U.S. dominance in the western Pacific, Xi's behavior throws up an increasingly urgent dilemma for America in how to slow China's military and economic expansionism.