A veteran US foreign policy adviser and a leading Filipino-American senator have expressed optimism on the resurgence of the US-Philippines relationship, calling the strained relations a "momentary phenomenon" that will eventually be hurdled by the two nations.

Charles Salmon, a former US foreign policy adviser to the commander-in-chief of the US Pacific Command, said the relationship between the two countries will remain strong and steady despite President Rodrigo Duterte's harsh rhetoric and uncertainties on President Donald Trump's foreign policy.

"I dont think there will be any fundamental change in the basic realization on the Philippines' part and (the US) part, that our bilateral relationship remains important and will continue to be important, and that we're going to continue to work together for stability in the Asia-Pacific," Salmon said.

“This is a momentary phenomenon. Our ships will find the safe harbor and a common harbor as we have always had since independence."

Salmon is also a former ambassador to many countries in the Asia-Pacific, with his last stop in Laos. He became director of the US Office for Philippine Affairs and US State Department Human Rights Office. He is now a senior fellow at East-West Center, a think tank based in Honolulu, Hawaii.

Meanwhile, Will Espero, the majority floor leader of the Hawaii senate, believes that Duterte’s rhetoric will eventually tone down.

"Yes you can throw out your chest, show your constituents that you're this brave courageous fearless man, but at the end of the day, I think he will probably have to tone it down," Espero said.

Espero hopes that both Duterte and Trump surround themselves with capable advisers and cabinet members who will put the ties of the two countries back on the right track.

"(Hopefully) they will listen to lawmakers and other opinion leaders in the country, and at the end of the day they will do what's right for the people of the Philippines and, in our case, for the United States," Espero said.

Salmon also believes Duterte and Trump have to come to terms on the issues of the extrajudicial killings and human rights in the Philippines to start reviving the longstanding alliance between the two countries.

"I can guarantee you that the human rights thing will still be a very, very important part of our dialogue, and I don’t think there’s any doubt that we are very concerned about the kinds of approach on the obviously serious problem of drugs that struck us as totally out of control," Salmon said.

But Dr. Marvin Ott, a geo-political analyst from Johns Hopkins University in Washington, D.C., said uncertainties still put a cloud of doubt on whether the bilateral alliance will still be the same as it was in the past 70 years.

"If you bring those two (Duterte and Trump) together, nobody knows what will happen. If the two of them met, they will probably make a series of decisions like that and I don’t know if they will end up yelling at each other or they end up arm in arm. I have no idea,” he said.