Looking out on Manila Bay from my hotel window, a floor above the suite used by Gen Douglas MacArthur during his stint as the military advisor to the Philippine Commonwealth from 1935 to 1941, you cannot help thinking how remarkably the strategic ground has shifted underfoot in this country.

Only six years ago, then-US Secretary of State Hillary Clinton had stood on the deck of a US aircraft carrier in the bay and meaningfully referred to the South China Sea as the West Philippine Sea.

It was a plain message to China from its treaty ally that sent a thrill through the Benigno Aquino III administration.

Getting no traction with Beijing on its maritime disputes, the latest being a confrontation in Scarborough Shoal the previous year when Chinese maritime surveillance ships blocked the Philippines Navy from stopping Chinese poaching vessels, Mr Aquino would eventually take the issue for international arbitration at The Hague.

He'd win his case handily.

Then, he'd watch his successor, President Rodrigo Duterte, stunningly put away the ruling and pronounce a reorientation of his nation's foreign policy.

From its traditional US moorings Mr Duterte moved it to one courting China, opening talks without any assurance of a Chinese pullback from the shoals and reefs it had seized.

The duty of explaining the Catholic nation's born-again foreign policy largely falls these days to Foreign Secretary Alan Cayetano, a 46-year-old lawyer, who served on the National Security Council that had decided to take China to court.

It was a move that so embarrassed and piqued the mainland that when Typhoon Haiyan blew through the Philippines in November 2014, its initial offer of aid was a paltry US$125,000, less than what was given by the Swedish furniture company Ikea.

Mr Cayetano was Mr Duterte's running mate in last year's presidential election, but came third in the vice presidential race.

The obligatory waiting period of a year having been completed he was tasked with the foreign ministry a few months ago, coincidentally as the Philippines got the chair of Asean as the grouping celebrated its 50th anniversary.

In a chat with select editors gathered for the inaugural Asean Media Forum on Friday (Aug 4) evening, he laid out the reasons for the Philippines' foreign policy U-turn, the Asean position on the South China Sea, and his own feelings for his boss.

The strategic objective of both gambits -- the go-hard with China that didn't work, and the current policy of engagement -- was to stop China and other claimants from building on more features in the contested South China Sea, he explains.

But the first approach only elicited distrust and instability, whilst disrupting daily lives as when fishermen were prevented from going to their traditional fishing grounds.

Some of the other claimants had also found "champions" in the Philippines to fight what was their battle too.

And eventually, the arbitral ruling that so went in Manila's favour amounted to nothing in tangible terms.

"Many think it's like winning in our local court where we have a sheriff, the police and an enforcement mechanism. But that's not the case in the West Philippine Sea-South China Sea. Enforcement is another issue."

Mr Cateyano does not say it outright but the message is unmistakable. When it came to the crunch, there was no one around to help the Philippines to enforce the law.

There's also a hint that while the Philippines does not press the arbitral ruling, it has not abandoned it.

"Last year, President Duterte said, 'Here is the ruling but I will keep it. There will be time when I will take it out. In the meantime, we will talk bilaterally'."

Meantime, Philippine fishermen are able to fish in their traditional grounds, the Coast Guard of the two nations are talking to each other to get grey hull Navy ships replaced by coast guard vessels, and Manila has received assurance that there will be no fresh building on Scarborough Shoal.

"We believe the Duterte strategy, without judging past strategy, is working not just bilaterally for China and the Philippines but for the whole region."

Then, he adds a further point. Brunei, Vietnam and Malaysia too have claims in the South China Sea, some of it overlapping. If the Philippines' ties with these nations could progress despite this, why should its ties with China alone be held hostage to the maritime dispute?

Superpowers, even if they are a treaty ally, pursue their own interests and do not always act like allies who've shared battles with you, he says.

Take the issue of some Filipino claims that go beyond the 200 nautical mile EEZ, based on the Treaty of Paris signed between Spain and the US.

Washington says even though it signed the treaty that defined those markers, Manila is not entitled to claim four of the features that lie within.

"Put yourself in Filipino shoes," he says. "Does it make a difference that you aren't claiming this for yourself but for international waters? The point is, you are not recognising our claims. So, it is normal that Filipinos have to find a foreign policy that forwards our national interests. Our national interests are served if there is peace and stab in the West Philippine Sea-South China Sea."

Against this background, as Asean chair, he says, his biggest challenge is to come up with language for the communique that will be acceptable to all.

"One man's weak statement is another's too-strong statement. The wording has to reflect what's happening on the ground."

What about his straight-shooting boss, under whose charge the Philippines has seen thousands of extra-judicial killings as he pursues his war on drugs?

Mr Cateyano suggests that Mr Duterte is a misunderstood personality.

"Despite what many may judge to be a man with meanness and violence in his language he is actually a peacemaker," says the foreign secretary. "To many Filipinos he is the epitome of a father who is very protective of his children."