Just when some of China's neighbors were seeking to curtail its expansionism, along came Rodrigo Duterte.
In less than three months on the job, the 71-year-old Philippine president has used expletives in talking about U.S. President Barack Obama and vowed to end cooperation with the U.S. military in both fighting terrorism and patrolling the disputed South China Sea. He has moved to boost economic and defense ties with China and Russia.
While Duterte is unpredictable — one day calling China "generous" and the next threatening a "bloody" war if Beijing attacks — his behavior has undermined U.S. efforts to rally nations from Japan to Vietnam to Australia to stand up to China's military assertiveness.