Rodrigo Duterte, President of the Philippines since June, visited China this week and signaled his interest in shifting Manila’s allegiance away from Washington toward Beijing. While his predecessor sued China in an international court to contest its expanded presence in the South China Sea (Beijing lost), Duterte, who has been ostentatious in his public derision of the United States, announced he would reopen direct talks with Beijing over the disputed waters. Is the U.S. about to lose a longstanding treaty ally? What is Beijing offering that makes Duterte’s posture worthwhile? Will other U.S. friends follow suit? And how should the U.S. respond?