For many accustomed to orthodox statesmanship, Philippine President Rodrigo Duterte is proving to be perplexingly, if not annoyingly, offbeat.

If the alleged extra-judicial approach of his anti-drug campaign has driven a wedge between himself and some traditional Philippine allies, most noticeably the United States, his foreign policy statements have left Washington nonplussed, trying to lip-read the intentions behind his explosive and often contradictory remarks.

To such an extent that Philippine Foreign Minister Perfecto Yasay has reportedly just assured Washington of Manila's continuous commitment to the Philippine-US alliance following Duterte's words in Beijing to "separate" from the latter.