From the American viewpoint, Duterte’s flip-flop — assuming it leads to a lasting strategic shift — is a potential disaster. Aligned with the United States and its regional allies, the Philippines can provide a vital platform to oppose Chinese aggression in the South China and East China seas.
If the Philippines becomes a Chinese satrapy, by contrast, Washington will find itself hard-pressed to hold the “first island chain” in the Western Pacific that encompasses “the Japanese archipelago, the Ryukyus, Taiwan, and the Philippine archipelago.” Defending that line of island barriers has been a linchpin of U.S. strategy since the Cold War. It now could be undone because of the whims of one unhinged leader.
China could either neutralize this vital American ally or even potentially turn the Philippines into a PLA Navy base for menacing U.S. allies such as Taiwan, Japan, and Australia. At the very least, the U.S. Navy will find it much harder to protect the most important sea lanes in the world; each year $5.3 trillion in goods passes through the South China Sea, including $1.2 trillion in U.S. trade.
Boot notes that this “massive geopolitical shift is entirely Duterte’s doing,” and that “the Philippine people remain largely pro-American.” With any luck, Duterte’s rule will be short, and the Philippines will return to the fold before any lasting damage is done.