I raise this conundrum today because I have a vague and weird feeling that Rodrigo Duterte has the potential at last to change all that. Behind the outrageous and foul-mouthed poseur who would be more than a match on stage for Donald Trump, there is perhaps the canny manoeuvring of a veteran politician. And as he steps this week onto a plane to Beijing, for his first official visit to China, he has in his hands the potential not just to change the balance of regional power, but to bring unprecedented benefits to the Philippines’ long-suffering people.

It is easy to be appalled and dismayed by the new Philippine president. His vulgar mouth and brutal incivility might work in the raw-knuckled frontier politics of south eastern Mindanao, but work less well in international political fora or when directed at the president of the United States. Having fathered four children out of wedlock, he is infamous for his philandering ways and crude sexual boasts, and acts as outrageously as Donald Trump.

Vigilante redress against drug sellers and users might be embarrassingly air-brushed away in remote Davao, but such a “policy” elevated to a national level is just a few dangerous steps away from the attention of international courts and ignominious prosecution for crimes against humanity. He is walking a dangerous tight-rope on his anti-drugs campaign, and I pray he knows that. His massive popularity ratings in the Philippines – with strong support from around three quarters of the population – have given him temporary licence, but sooner rather than later his people will expect more from him. If he proves to be a “one-trick pony” focused exclusively on drugs and law and order, then his positive ratings will be short-lived.

This is why, before judging him, it is important to review what he has achieved in Davao since he first became mayor in 1988. Duterte is as close as you can get in Davao to political “royalty”. His father, Vicente, was once provincial governor to Davao. His daughter Sara is also prominent in local politics. His reputation may have been built on a long-standing “law and order” and anti-drugs platform (he has tough anti-smoking policies in place too) but to his credit Davao counts among the Philippines’ better performing municipal economies. He has built a better transport infrastructure than can be boasted by most municipalities in the country, and Davao is, for example, one of the few regions that have buried electricity and telephone cables underground – eliminating the shanty raggle taggle of power and telephone lines that decorate most Philippine cities. As a Financial Times commentator noted last week: “He has shown a common touch in promising measures to improve the everyday lives of ordinary Filipinos by restarting delayed rail projects and easing Manila’s notorious traffic gridlock.”

But it is on the international stage that Duterte truly has the potential to transform his country’s reputation, and the livelihoods of the Filipino people. For this he has to thank his predecessor Benigno Aquino III for choosing to take the country’s long-standing spat with China over territorial claims in the South China Sea to the Court of Permanent Arbitration in the Hague, rather than to wage a high-seas war of attrition between coast guards and fishing boats. China refuses to acknowledge the Hague ruling in favour of the Philippines’ complaints, but there can be no doubt that it has cut deep. Beijing likes to be on the right side of International Law, and prides itself on observance, so the potential for the ruling to affect Beijing’s behaviour cannot be underestimated.

The Hague ruling puts in Duterte’s back pocket a basis for diplomatic leverage on China that no predecessor has had in three decades. If, as the US advocates, Duterte bangs the table for Beijing to adhere to the Hague ruling, he will get nowhere, and is likely to spend his remaining years as president arm-wrestling a gorilla that he cannot possibly out-muscle. But if, on the other hand, he discretely uses the back-pocket leverage of the Hague ruling to agree a practical “modus Vivendi” in the South

China Sea, then the rewards are likely to be huge. The Philippines is not yet a member of the China-led Asian Infrastructure Investment Bank (AIIB), but as soon as it is, China will certainly make sure the bank’s purse strings are generously open to a long queue of long-delayed and badly-needed Philippine infrastructure-building projects.

It will be a tough early test for Duterte and his freshman foreign minister, Perfecto Yasay, but the potential exists for the Beijing meetings this week to deliver massive benefits to the Philippine people, and to elevate Manila to being a significantly more important power-broker in the Asia-Pacific region. This must in part explain recent posturing against Obama, the US military, and the Philippines traditional “little brown brother” relationship with the United States. Yasay might have been blustering somewhat when he complained that “America has failed us”. And Duterte does not in truth want Obama or any other US president to “go to hell”. But a looser dependency on the US, and a little “entente” with China, might do the Philippines – and the rest of us in Asia – more good than harm.

David Dodwell researches and writes about global, regional and Hong Kong challenges from a Hong Kong point of view