Generally, American Presidents arrive in China in a position of superiority, backed by US economic might, the unmatched capability of American armed forces and the weight of more than 70 years of global leadership.

But the questions being asked about who is the dominant partner in the Xi-Trump relationship reflect the impact of the political firestorm raging in Washington and the reality of geopolitical change being wrought by China.

Trump bristles at the idea that he is the junior partner in the relationship with Xi, who was recently dubbed by "The Economist" as the world's most powerful man, a title normally conferred on the US President.

The President was asked by reporters what he thought about the remarkable run Xi is having as he headed to Asia on Air Force One.

"Excuse me, so am I," Trump said, citing the "highest stock market in history, lowest unemployment in 17 years, a military that's rapidly rebuilding, ISIS is virtually defeated in the Middle East. We are coming off some of the strongest numbers we've ever had," Trump said. "He respects that, and he's a friend of mine. We're friends."

More nuanced than it appears

Trump is partially correct that the balance between the US and China, an often adversarial diplomatic dance between partners locked in an interdependent economic embrace, is more nuanced than it appears.

Despite Trump's personal troubles, the United States remains the most powerful military force in Asia, and ensures freedom of navigation in sea lanes that underpin global trade. Its seven decades of security guarantees transformed the region into the world's most dynamic engine of growth.

While US allies may be perturbed and sometimes confused about Trump's approach, they dearly want an engaged US in Asia and see Washington as a bulwark against dominance by Beijing, a factor that confers considerable geo-political power on the President.

Trump's plan for military spending sprees, including on new Navy ships, also sends a signal of resolve amid China's own naval buildup and its willingness to project power in support of controversial sovereignty claims that have alarmed US allies amid new tensions in the South China Sea.

While Xi is incredibly powerful, some of the veneration and instant analysis of his position may overestimate his strength, since politics, even in authoritarian China is more complex than it looks. Power in the country is not just monolithically consolidated in a single man.

"There's a lot going on in China behind the scenes that suggests that, while President Xi has amassed enormous institutional power, that there are some pretty significant pockets of discontent," said Elizabeth Economy, director for Asia Studies at the Council on Foreign Relations.

"He faces a number of significant environmental and economic challenges. So the difference between the two leaders as they sit down ... may not be quite as great as we would assume it to be," she said.

Xi's added muscle also brings new pressures that Trump could exploit.

"One downside of heavy consolidation of power is that there's no one else to blame inside your system, especially on trade policy and on North Korea policy," Christopher Johnson, a former CIA China specialist, now at the Center for Strategic and International Studies.

"So if, in the past, as we've seen from Chinese government administrations past, if you want to say, well, 'I'd love to help you on trade but the state-owned enterprises are tough, or I'd love to help you on North Korea but my military won't let me,' it's a little difficult for Xi Jinping to be able to make that case," he said. "I would expect President Trump to play that card in his discussions."

"It has always been as big a risk to overestimate China's power as it is to underestimate its potential. Now the same could be said of Xi," Paulson wrote.

Leap in Chinese influence

Still, it's clear that the Trump administration has come to Asia recognizing the leap in Chinese influence, as the communist giant emerges as a regional superpower with global ambitions under Xi's "Chinese dream" concept of national renewal.

US Presidents have since Richard Nixon's opening to communist China in the 1970s generally been ascendent in dealings with their counterparts in Beijing.

A sign of their relative power has been their preoccupation with managing China's rise without inciting a clash with the dominant superpower, the US. Trump, for reasons far deeper than his own political woes, will confront a far different challenge in dealing with a newly potent China.

The White House is touting a new concept, referring to Asia as the Indo-Pacific region, effectively bundling US ally, and Chinese adversary India into the pan-Asian security conversation as a regional power and balance against Beijing.

One of the most interesting questions at the summit will be whether Trump signs up to China's desire to rebrand Sino-US interaction as a new "great power" relationship. Beijing's pre-occupation with diplomatic protocol and linguistic precision often appears obtuse to outsiders. But the tussle over definitions disguises significant strategic implications.

Obama administration officials were for instance wary of using China's preferred terminology, believing that it could imply the carving up of the world into zones of influence, and be seen as a way for China to erode US strategic weight in Asia.

It will also be fascinating to see whether Trump can win a payoff for his effusive praise of Xi after he lauded the Chinese leader's "elevation" in a tweet and recently compared him to an all-powerful king.

Trump -- who last week bemoaned constraints on his power and inability to order the FBI and Justice Department to probe Hillary Clinton and often seems to admire authoritarian leaders -- appears to envy Xi's control.

China, meanwhile, understands Trump's keen sense of how he is treated by others.

It is billing the trip as a "state visit plus" and will shower Trump with all the pomp and spectacle China's history and culture can muster, at iconic sites like the Great Hall of the People and the Forbidden City.

The question is whether the outpouring of respect and adulation will distract the US President, and perhaps temper the hard line on trade and North Korea that he is intending to deliver.

If not, this week's summit may be seen as a high point of a US-China relationship that faces a significant risk of degenerating into tension and recrimination and a genuine great power rivalry.

"President Trump has found a way to separate what seems to be a real admiration for President Xi Jinping from his real unhappiness with Chinese policy, he distinguishes between the two," said Economy of the Council on Foreign Relations.

"And I think at this meeting it will be interesting to see ... whether President Xi actually delivers on some of the things that President Trump is going to press him on. I think this is the rubber meets the road at this moment," she said.