Barack Obama delivers an address at the Lao National Cultural Hall, on the sidelines of the ASEAN Summit, in Vientiane, Laos, September 6, 2016. REUTERS/Jonathan Ernst A pivot to Asia was supposed to be one of the signatures of President Barack Obama's foreign policy. But the last Asia trip of his presidency, which came to a close Thursday, has been marred by controversy.

Obama had to cancel a meeting with Philippines President Rodrigo Duterte after Duterte called him a "son of a whore."

He failed to reach a deal with Russian President Vladimir Putin on a ceasefire in Syria.

And he caused an uproar in China by exiting Air Force One through the belly of the plane rather than down a large staircase that would have provided a better photo op.

And a rising China might make officials there more willing to take risks.

"The negotiating environment for the US is getting more challenging," geopolitical expert and Eurasia Group President Ian Bremmer told Business Insider in an email. "The world is more 'multipolar,' and China in particular is getting much more assertive — with the economic (and, in Asia, military) power to back it up."

This, along with Obama's struggles to pass the Trans-Pacific Partnership trade deal, contributes to the difficult conditions Obama has faced during the Group of 20 summit in Asia.

"Even if the US made all the right moves, these would be harder trips than they used to be," Bremmer said.

Philippine President Rodrigo Duterte speaks at a news conference in Davao. Thomson Reuters

The Philippines president

Duterte railed against Obama while he was talking to reporters, telling press that if Obama asked him about human-rights issues during their meeting, he would curse at him.

Duterte said he would call Obama a "son of a b----" if such a line of questioning was raised.

Obama called off his meeting with Duterte, and the Philippines government issued an apology, saying that the press reporting that Obama would "lecture" Duterte on extrajudicial killings "led to his strong comments, which in turn elicited concern." The incident made headlines in the US as well as Asia.

But Obama canceling the meeting doesn't necessarily signify any trouble with US relations with the Philippines.

"Duterte misspoke," Bremmer said. "He'll do that a bunch. But I'd bet they'll talk and make up before Obama leaves office."

Ben Rhodes, Obama's deputy national-security adviser, told reporters that the meeting with Duterte was canceled because the administration didn't want the focus to be on Duterte's controversial comments.

"All of the attention frankly was on those comments and therefore not on the very substantive agenda that we have with the Philippines," he said.

Obama and Duterte did end up meeting informally on the sidelines of the G-20 summit.

Russian President Vladimir Putin meets with US President Barack Obama on the sidelines of the G20 Summit in Hangzhou, China, September 5, 2016. Sputnik/Kremlin/Alexei Druzhinin/via REUTERS

The Syrian ceasefire

There was also hope that Obama and Putin might come to agreement on a Syrian ceasefire at the G-20.

Russia has been supporting Syrian President Bashar Assad in the country's civil war, and the US has been trying to mediate between the regime and the opposition, which is demanding that Assad step down. Both Russia and the US are also fighting ISIS and Al Qaeda-linked terrorists in Syria.

In the end, Obama and Putin couldn't close the "gaps of trust" that exist between the US and Russia in Syria, Obama said.

"We have had some productive conversations about what a real cessation of hostilities would look like to allow us to both focus our energies on common enemies," Obama said at a press conference Monday. "But given the gaps of trust that exist, that's a tough negotiation. We haven't yet closed the gap."

Syria negotiations involving the US and Russia are scheduled to continue later this week. But US officials have said that eventually the US might decide that pursuing an agreement with Russia isn't worth it.

Some foreign-policy experts consider the humanitarian crisis in Syria one of the failings of Obama's presidency.

The Obama administration has often touted its 2013 deal that was supposed to remove chemical-weapons stockpiles from Syria and prohibit Assad's forces from using them against civilians in the future, but a recent UN report confirmed that the regime has used chlorine gas multiple times since then.

Barack Obama arrives on Air Force One for the 2016 G20 State Leaders Hangzhou Summit at the Hangzhou Xiaoshan International Airport on September 3, 2016, in Hangzhou, China. Etienne Oliveau/Getty Images

The landing in China

More negative headlines came with the botched landing in China.

Obama typically exits Air Force One on a rolling stairway flown in by the military, but Chinese officials reportedly told US officials shortly before Obama arrived that he couldn't use those stairs. The US agreed to use a Chinese stairway, but then the local driver was not able to communicate with White House officials, according to The New York Times.

The mix-up resulted in Obama exiting the plane on a smaller staircase from a less-visible part of the aircraft, as he does when he arrives in a location where there are concerns for his safety, according to The Times.

Some in the US interpreted the snafu as a snub from China, and Republican presidential nominee Donald Trump seized on this embarrassing moment during his national-security forum on Tuesday.

"Think of it — lands in Cuba, doesn't have high officials to greet him," Trump said, mocking Obama. "Lands in Saudi Arabia … and they don't have the high officials to greet him, the highest officials."

Then, in China, Trump said, "They won't give him stairs to get off the plane!"

There was also a tussle when Chinese officials mistakenly tried to prevent Obama national-security adviser Susan Rice from walking to the president's motorcade. While the incident was unfolding, a Chinese official said loudly to a White House aide, "This is our country. This is our airport." The story made headlines across China.

While US relations with China are often tense, the pressure might be increasing as China shows it power.

"I don't see China sparring with the US over Obama's visit as anything new — it happens every trip. It just ratchets up incrementally as China gets more powerful," Bremmer said.

US President Barack Obama meets with the leaders of the Trans-Pacific Partnership countries in Beijing, November 10, 2014 Kevin Lamarque/Reuters

The Trans-Pacific Partnership

The Trans-Pacific Partnership will be key to America's relationship with Asian countries going forward, Bremmer said.

"A lot depends on TPP," he said. "If it doesn't get done, China will become the fall-back leader for Asian economic architecture. And US relations with many countries in the region will slip."

Obama is pushing for the controversial trade deal that would lower tariffs for 12 countries around the Pacific, not including China. Obama is attempting to get the deal through Congress during the lame-duck period before he leaves office.

"I believe that we'll get it done, but it's always going to be hard," Obama said Wednesday in Laos. "Nothing is easy in the US Congress right now."

Both Trump and his Democratic rival, Hillary Clinton, say they oppose the deal.

"The whole TPP agreement really isn't about workers, who are taking it on the chin whether it gets concluded or not," Bremmer said. "It's about America's position in Asia."

Obama still has a few months to cement his legacy in Asia. But with the TPP still hanging in the balance and his rocky final trip to the region, the question of whether he'll be able to successfully pull off a pivot is open.