Duterte is a highly criticized leader. It is said that he is the Trump of the Philippines, but we can ask the question if Trump is not the Duterte of the United States. Normally we talk about Russia, China, USA, and other major geopolitical changes. Unfortunately, the Philippines are highly over looked.
Duterte is playing the geopolitical game very well. With no military capacity and the ongoing internal conflicts with Muslim terrorists, Duterte is capable of maximizing his position as a partner of the United States and China.
The more interesting part is the position they play in the conflicts they are in. The Philippines is using the navy of Japan and China to protect the islands. But the Philippines are in a conflict with Japan and South Korea. Both are key Alliance partners of the United States in Asia.
What makes the situation for the Philippines even more difficult is the fact that this is an Island nation. A nation with a long-lasting history of military coops and dictatorships.
The risk of the Philippines flipping to China as its key Alliance is not big into my opinion. First of all, is there a territorial dispute between the Philippines and China. So when they form an Alliance than they need to solve the dispute or look the other way. But none of the countries is known for looking the other way around.
But there is a more important reason. The United States is over 8,000 miles away. The USA is not interested is troops on the ground or opening another military base. But the status qua remaining is very important. I assume the United States has learned the lesson from the New Zeeland flipping.