Philippines President Rodrigo Duterte speaks as he displays a picture of a Glock 30 pistol, received as an award, during his visit at the Philippine Marines headquarters in Taguig city, south of Manila. (Francis R. Malasig/European Pressphoto Agency)

If you could sum up the U.S. response to President Rodrigo Duterte in one phrase, it might be something like, “For real?”

Duterte swept to power in July, promising to ride a Jet Ski through the South China Sea and kill 100,000 criminals in six months. At his first big summit, he lashed out at President Obama, using a slang term that translates, roughly, as “son of a whore.”

In the weeks since Obama canceled a meeting with him, Duterte has made big announcements on bilateral ties, including Wednesday’s promise to cancel U.S.-Philippine military exercises after next year, and his call for U.S. Special Operations forces to leave Mindanao, only to have his Foreign Affairs Department back off the news right away. 

The flip-flops have the press in a whirl. “It’s like ‘Keeping Up With the Kardashians,’ ” joked Richard Javad Heydarian, an assistant professor of political science at Manila’s De La Salle University. 

But stories about Duterte’s “antics” misread the man and the stakes. The president of the Philippines is very much for real and presents a real diplomatic challenge to Washington as it pursues its turn toward Asia, and China pushes back.

At stake are plans for a greater U.S. military presence in the Philippines under a new defense agreement that came into force this year.

Duterte said Wednesday that joint military exercises scheduled next month between the Philippines and the United States will be the last because he does not want to upset China. On Thursday, Foreign Affairs Secretary Perfecto Yasay said he had not heard the comment and insisted Duterte would respect the Philippines’ commitment to cooperate with the United States.

Earlier in the week, Duterte vowed to “cross the Rubicon” in terms of U.S. ties by deepening his relationships with Russia and China — a comment that Yasay called “dramatics.”

The tone has diplomats on edge. “U.S. officials are quite concerned,” said Jose L. Cuisia, the Philippines’ former ambassador to the United States. “And so are my colleagues at Foreign Affairs.”

To understand what’s driving Duterte’s behavior, consider two things: He is wildly popular at home, and he plans to visit China in October.

He has the support of millions of Filipinos. He campaigned for president on a promise to “kill all” the country’s criminals. Since he took office three months ago, at least 3,300 suspects have been killed, either shot in police operations or gunned down by plainclothes assassins.

The United States, the European Union and the United Nations have spoken out against the violence, but many crime-weary citizens support the “war on drugs,” and Duterte has high approval ratings.

Duterte’s popularity and political acumen have helped him quickly build alliances in Manila. As the Senate and the House fall in line, he is gaining the political support necessary to push ahead with his platform — and the cost of crossing him grows.

Analysts say they think Duterte will continue to consolidate power. “He’s the only game in town right now,” said a senior Western diplomat in Manila who spoke on the condition of anonymity because he is not allowed to speak to the media. 

“There is nobody else.”

That clout makes it tougher for the United States and others to take public stands against the president or his policies.

Though the vast majority of Filipinos have a positive view of the United States, calling out perceived U.S. hypocrisy seems to serve Duterte well, bolstering his image as a political outsider who challenges the status quo.

Realizing this, perhaps, Washington has thus far responded cautiously, stressing long-term stability in ties. “Our relationship with the Philippines is broad, and our alliance is one of our most enduring and important relationships in the Asia-Pacific region,” said Molly Koscina, a spokeswoman for the U.S. Embassy in Manila. 

Though Duterte is seen by some outsiders as irrational, his anti-American rhetoric may be a deliberate bid to build trust with Beijing, analysts said. 

His predecessor, Benigno Aquino III, took a hard line on China, angering Beijing by challenging its South China Sea claims at an international court.

Duterte wants to improve ties; during his campaign, he said he would consider shelving the South China Sea dispute if Beijing built a railway on the island of Mindanao. 

On his first visit to China as president, in the third week of October, he is expected to focus on the South China Sea, where Chinese boats are blocking Filipino fishermen from waters off the Scarborough Shoal.

If he has any hope of getting Filipino boats back to those fishing grounds, Duterte will need to show China goodwill without totally alienating the United States.

De La Salle University’s Heydarian ventured that promising, say, to move the annual military exercises from disputed waters to a different coast could do just that. 

“He is signaling to China that he is a different Philippine president, an independent sovereign leader, and that [he] is willing to tinker with certain aspects of the U.S.-Philippine relations to please the Chinese,” Heydarian said.

“He is not saying he will downgrade relations with the U.S. — just that he’s willing to tinker.”