By The Economist

“Transformative”, “historic”, “eloquent”: such are the compliments which American officials these days shower on Ferdinand Marcos Jr., the Philippines’ president. After a six-year dalliance with China by his predecessor, Rodrigo Duterte, Mr Marcos’s re-embrace of America is a great geostrategic gift. Never mind the early doubts about his leadership and his effort to rehabilitate his late father, a Philippine dictator who fled to Hawaii in 1986.

“Bongbong”, as the president is known, has padlocked the “first island chain” around China. From Hokkaido in Japan to Palawan in the Philippines, the line of American friends and allies may prove decisive in any future war.

For now the contest is in the grey zone, between peace and war. China’s coastguard regularly harasses Filipino vessels with water cannon near disputed shoals in the South China Sea. But at the Shangri-La Dialogue, an annual defense talkfest in Singapore that ended on June 2nd, China got the political blasting.

Mr Marcos denounced China’s “illegal, coercive, aggressive and deceptive actions”. Lloyd Austin, America’s defense secretary, concurred, calling China’s behavior “dangerous, pure and simple”. A South Korean academic was cheered for asking Admiral Dong Jun, China’s third defense minister in less than two years: “How can we trust you when your words and your actions are totally opposite?”

Indeed, Chinese military officials conveyed contradictory messages at the meeting. They sought to cast China as the responsible superpower, resuming military-to-military contacts with America and reassuring fellow Asians of China’s peaceable nature. Yet they kept snarling at those who cross them. Taiwanese “separatists”, foremost among them President Lai Ching-te, “will be nailed to the pillar of shame in history.”+ Mr. Marcos was “inviting wolves into our house and playing with fire”. Both were being incited by America, the cause of “conflict and chaos in our region”.

No words could reconcile China’s claim to champion international law with its attempt to seize almost all of the South China Sea. In 2016, an international arbitration tribunal ruled that China’s claims in the Philippines’ exclusive economic zone breached the UN Convention on the Law of the Sea. (China calls the ruling “illegal”.) Mr. Marcos’s policy of “transparency”—confronting the Chinese at sea and publicizing the clashes—is a striking form of legal and information warfare.

Matters may be entering a more perilous phase, however. China’s coastguard has threatened to start arresting “trespassers” in the regions it claims from June 15th onwards. If a Filipino were killed by “wilful” Chinese violence, Mr. Marcos warned, that would be “very, very close to what we define as an act of war”; America would “hold that same standard”.

Hearts may cheer Bongbong’s daring, but heads must question his reckless words. He cannot enforce his red line. America will not go to war over a dead fisherman. “Very foolish,” thought one prominent attendee. “Hollywood” bravado, snorted another. As ever with allies, the weaker one fears abandonment and the stronger dreads entanglement. Mr. Austin had to paper over the gap. He said America’s defense treaty with the Philippines was “ironclad”, though “Our goal is to make sure that we do not allow things to spiral out of control.”

For all its economic and military power, China is hobbled by ideology. Unwilling to give an inch on dubious “historic rights”, even in minor shoals, China disappointed Mr. Duterte and pushed Mr. Marcos into America’s arms. Bewildered Chinese officials seek conspiracies to explain this turn of events. They should instead look in the mirror.

The cost of China’s bone-headedness is clear. America, Japan and Australia are hastening Philippine forces’ shift from counter-insurgency to territorial defense. America has gained access to nine Philippine bases, some facing the South China Sea and Taiwan. In recent exercises there, it deployed for the first time a new missile system able to hit China. In the event of war—over, say, an invasion of Taiwan—Chinese forces could be fired upon from more places and find themselves bottled up in home waters.

Yet uncertainties abound. America cannot be sure which allies will really fight. Mr. Marcos’s successor could flip back to China. And Donald Trump, should he be elected president this year, could throw it all away in his disdain for needy American allies. After all, China has shown how easy it is to lose friends.