Philippine President Rodrigo Duterte is continuing with his series of tirades against the US and his statements are injecting uncertainty into a longstanding strategic partnership between the two countries. 

In his most recent statements on Tuesday in the capital Manila, Duterte said that US President Barack Obama could "go to hell" and that the Philippines would be willing to acquire arms from China and Russia if the US was unwilling to provide them. "Eventually I might, in my time; I will break up with America… I would rather go to Russia and to China," he said. 

On Sunday, October 2, Duterte amped up his rhetoric, saying that the US "better think twice" or he would ask that the Americans "leave the Philippines altogether." He continued saying, "The Americans, I don't like them... they are reprimanding me in public. So I say: 'Screw you, fuck you'." 

Last week, during a speech in Vietnam, Duterte said that an eight-day joint military exercise currently taking place between a combined 1,500 US and Philippine troops would be the last during his term. Although his foreign secretary says no final decision has been made, Duterte's remarks raised questions if other annual US-Philippine military exercises would be called off. Duterte has also threatened to evict US special forces from bases in the southern Philippines. 

All talk and no action? 

Duterte's rhetoric has yet to be translated into changes in policy, but the uncertainty surrounding his willingness to follow through on his statements is cause for concern. 

No one knows what exactly Duterte's intentions are, says Gregory Poling, Director of the Asia Maritime Transparency Initiative at the Center for Strategic and International Studies (CSIS). "And this is a big part of the problem. Alliance management thrives on consistency, which is desperately lacking under Duterte," he told DW.

"His alternative strategy seems to hinge on hoping that China will cut a fair deal in the South China Sea - but there has been no indication that Beijing is actually willing to negotiate any of the core issues in the South China Sea," said Poling. 

This week's Philippine Amphibious Landing Exercise (PHIBLEX) is part of the Enhanced Defense Cooperation Agreement (EDCA), which the US and Philippines signed in 2014. The agreement was partially in response to Chinese territorial aggression and the recognition that building mutual capacity was necessary. 

Leverage vis-à-vis Beijing 

Despite Duterte's tough talk, he has assured that he would not absolve the Mutual Defense Treaty in place with the US since 1951. But even if the Philippines were to maintain this longstanding framework, hands-on exercises between troops like PHIBLEX would be necessary to sustain alliances.

"The alliance will continue to exist on paper, but would be badly degraded," said Poling about the possible discontinuation of military exercises. "You can't maintain an effective military alliance if your two militaries can't work together."

The relationship with the Philippines is a key component of the current US administration's "pivot to Asia" or a rebalancing of US foreign policy goals to the region from the Middle East. The Philippines is currently the third-largest recipient of US military aid in Asia, after Afghanistan and Pakistan, with $120 million allotted so far in 2016. Deterioration of military cooperation would have consequences for both sides, observers warn. 

"China will certainly cheer," said Poling. "The threat of US intervention has been the only real deterrent to China using force against the Philippines in the South China Sea; it is why there are still Filipino marines stationed aboard a naval vessel at Second Thomas Shoal and why there is not a Chinese artificial island at Scarborough Shoal. Without the alliance, Manila has little or no leverage vis-à-vis Beijing." 

A diplomatic tightrope

Recent US criticism of the drug war in the Philippines has irritated Duterte, who took office in June 2016 and began a nationwide vigilante campaign against drug dealers and users with an estimated 3,100 people having been killed in 10 weeks.  In recent weeks, Duterte has made vulgar statements toward US President Obama and made favorable comparisons with Hitler. And although there have been no official notices issued by the Philippine government, US officials are walking a diplomatic tightrope in order to avoid further agitating the Philippine firebrand. 

"US officials continue to keep calm, respond to each of Duterte's tirades in a measured way, and reiterate the US commitment to the alliance," said Poling. "But none of that seems to be calming Duterte."

"Sometimes you have to hold your nose about the individuals and deal with the countries," Frank Jannuzi, a former Senate Foreign Relations Committee Asia specialist, told Reuters news agency. "The United States doesn't have the luxury of writing off the Philippines, so we have to find a way to deal with this extraordinarily distasteful leader while still conveying our opposition to his human rights policies." 

Domestic consequences 

If Duterte breaks the EDCA agreement or moves away from cooperation with the US, it could put his popularity at home in jeopardy. Along with military aid, humanitarian relief was a large part of the agreement.  

"What really made EDCA possible was the US response to Typhoon Haiyan/Yolanda, which reminded Filipino citizens of the public goods that the US, and only the US, can deliver during an emergency," said Poling. "That is why humanitarian assistance and disaster relief remain such a big part of EDCA planning, despite all the media focus on the South China Sea."

"What is clear is that when it comes to foreign policy, Duterte is out of step with his own cabinet officials, the Philippine military brass, and the vast majority of Filipinos according to polls," added Poling.