There was a renewed pledge to cut greenhouse gases by the U.S. and China, the world’s two biggest polluters. Chinese President Xi Jinping and Japanese Prime Minister Shinzo Abe smiled for the cameras in a makeup session for previous chilly meetings. But for all of Beijing’s assiduous preparation for the Group of 20 (G-20) summit in Hangzhou that convened world leaders in the lakeside Chinese city, diplomatic wrangles and unrealized ambitions dominated the proceedings.

The Chinese government gave grand import to the Sept. 4 to 5 meeting, with the official motto: “Towards an innovative, invigorated, interconnected and inclusive world economy.” “Against risks and challenges facing the world economy,” President Xi said in Hangzhou, “the international community has high expectations of the G-20 in the Hangzhou summit.” Nevertheless, controversy dogged the meeting from the moment Barack Obama emerged from Air Force One for what will likely be his last trip to Asia as U.S. President. Because of a fracas over what stairs he would use to exit his plane, Obama ended up exiting via the belly of the aircraft rather than receiving a grand reception from the higher door — as is normally the case with visiting heads of state.

Read More: China’s Hangzhou Clears Out Pests — and People — as It Prepares to Host the G20 Summit

Both sides say that the incident resulted from a dispute over whether a non-English-speaking driver could roll a stairway up to Air Force One. “I think if only the American group had respected the working arrangements first made with China then this wouldn’t have occurred,” said Chinese Foreign Ministry spokesperson Hua Chunying on Monday.

But there is disagreement over why another staircase, which the U.S. ships in to use with the plane, was not used in the first place, as normally happens when an American President travels to foreign countries. “You saw that all the other country leaders all used the stairs that China provided,” said Hua. “So why was it only the United States that didn’t?” A Chinese international-relations professor who advises the Chinese Foreign Ministry and who does not want his name used because of the sensitivity of the issue, blamed an overeager Chinese security apparatus for declining to follow standard American protocol. “My understanding is that everything was agreed through the normal diplomatic channels and then the security side stepped in,” says the professor. “I don’t believe this was done to embarrass Mr. Obama. But it doesn’t look very welcoming, I know.” (In a separate incident, a Chinese official, who was shepherding a high-level American group to the Hangzhou state guesthouse where Obama and Xi were to meet, nearly got into a physical fight with Chinese guards blocking their way.)

For his part, Obama shrugged off the airport incident. “I wouldn’t overcrank the significance of it,” he said, even as he admitted that “the seams are showing a little more than usual in terms of some of the negotiations and jostling that takes place behind the scenes.” While briefly acknowledging sticking points in the Sino-American relationship, such as human rights, accusations of Chinese cyberhacking and tensions in the contested South China Sea, Obama presented an upbeat assessment of bilateral affairs. “We have seen steady progress during the course of my presidency,” he said during remarks ahead of a bilateral meeting with President Xi in Hangzhou, “and during the course of the multiple meetings that you and I have had.”

Read More: Hong Kong Legislative Elections Have Given Voice to a New Political Generation

But it is hardly “steady progress” that has come to define the U.S.-China relationship, especially since Xi has pursued a more assertive leadership both at home and abroad. Amid a mounting crackdown on Chinese that dare to question the Chinese Communist Party, Xi’s administration has attacked so-called Western values, alleging freedoms of speech, assembly and the like are part of a sinister plot to subvert China. Some of the anti-American screeds emanating from the Chinese state sound like Cultural Revolution–era dogma rather than reflections of a 21st century in which China is a globalized economy that depends on trade with the West. From the South China Sea — where the Chinese have built de facto military bases in disputed waters, flouted an international tribunal judgment on territoriality and dispatched boats near a contested shoal off the Philippine coast while the G-20 Hangzhou summit was under way — to the halls of international finance, the U.S. and China have consistently failed to find common ground. The one notable exception appears to be fighting climate change by formally ratifying the Paris pact.

Obama arrived in China with his effort to launch a Trans-Pacific Partnership trade pact stymied at home. The agreement extends to 12 countries with one power conspicuously missing: China. But congressional animosity toward the free-trade agreement is fierce, and both Hillary Clinton and Donald Trump have signaled their opposition. Obama has little leverage to push forward with what was supposed to be the economic centerpiece of his foreign policy pivot toward the Asia-Pacific region. Meanwhile, China’s attempt to put its stamp on global finance received a further boost on the eve of G-20 when Canada applied to join the nascent Asian Infrastructure Investment Bank. Among major economies, only the U.S. and Japan have refrained from joining the Chinese-led lending institution.

Read More: North Korea Fires Three Missiles While the G-20 Gathers in China

Meanwhile, on the final day of the G-20 summit, North Korea fired a trio of ballistic missiles toward the Sea of Japan. Beijing had used the Hangzhou confab to reiterate its opposition to the proposed deployment in South Korea of the U.S.-backed THAAD antimissile system. But Seoul says it needs to boost its defenses against the North Korean regime. China’s erratic neighbor, which counts Beijing as its only patron, knows how to spoil a party. But a missile launch was perhaps the least of worries for China. On Sept. 5, results trickled in from elections in Hong Kong that gave voice to sentiment against Chinese domination of local politics. Chinese — granted ones from a former British colony — had expressed their displeasure with leaders in Beijing. Later on Monday, Obama and Russian President Vladimir Putin huddled in Hangzhou for a sideline meeting. However, no deal appeared to follow on alleviating the humanitarian crisis in Syria. Despite all the hype and hope Beijing attached to its hosting of the G-20, the world’s leaders were struggling for significant economic or geopolitical breakthroughs. Paris has a climate deal named after it. Fair or not, Hangzhou may have to make do with a controversy over a flight of airplane stairs.

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