The thing about Duterte is this -— He looks like he’s trying to distance himself from the West.
Trump invites him to come to Washington DC and he goes to Russia to meet Putin instead ( he had to cut short his visit because of what happened in Marawi ).
He’s very angry at the West ( EU and the USA ) for calling him put on his so-called extra-judicial killings in his war on drugs.
Yet, he needs military support ( arms, planes, etc. ) to fight a Muslim insurgency in the south. So, where does he go for help? Russia!
Go Figure...
To the best of my knowledge, Trump has done the opposite. He has praised him for his anti drug efforts. China is a rising power. Some countries are going into their orbit. China is building artificial islands and plans to eventually take Taiwan. They feel it will protect them from any hostile naval activity. Further it will allow them to project their power and bully. Giving them the Philippines would be a blunder along the lines of losing Iran or Cuba. The Philippines’ location along with Chinese maritime claims and possessions would really squeeze South Korea and Japan.
Additionally, I read a survey a year or two ago that showed the Philippine people have the most pro-american opinion of any. Their people like America, their country is in a strategic location and we have a long and mostly friendly history with them. We should not bother ourselves with projecting our values of justice onto them. That won’t accomplish anything but push them into China’s orbit. We have no leverage to make them change their behavior and Duterte won’t be president forever. He’s 70 years old iirc. He’s unlikely to be able to serve more than two terms as president.
America should focus on the big picture of global security from the vantage point of American, South Korean and Japanese needs. This also coincides with what is best for Filipinos. They are a free people and should not become a colony/slave of China.
Russian small arms function well in tropical climates.