Yesterday I witnessed the difference between China and the United States. I will write about it on Sunday.

When I listened to the opening remarks at the summit by Xi Jinping and Donald Trump, I was immediately reminded of what Ben Rhodes — one of Obama's closest advisers — recounted about the American president's state visit to Beijing in 2014.

Yesterday, a stark contrast came into sharp relief.

On one side, the Chinese leader addressed the international situation, going so far as to invoke the 'Thucydides Trap'. On the other, Trump dwelt on the children's parade welcoming his arrival and the warm rapport between the two presidents, as though they were old friends reuniting after a long absence.

Xi Jinping speaks the language of diplomacy and statecraft; Trump that of business and media spectacle.

This is not merely a clash between two cultures or two worldviews. It is also a profound divergence in the very practice of politics.

In the West, political leaders increasingly calibrate their communication and their actions toward entertainment and the logic of the influencer. In China, the Communist Party must legitimise itself as the guardian of a civilisation thousands of years old.

Xi reinforces this tradition by conducting himself in the manner of China's ancient philosopher-kings, whose duties included applying Confucian values to governance and the art of statecraft.

'In Chinese political culture, the top leader should not concern himself with the mundane matters of daily life' said Zoe Liu, senior research fellow at the Council on Foreign Relations. 'They are the "sons of heaven" and are expected to engage with philosophical questions.'

This became immediately apparent to President Obama during his 2014 state visit to Beijing. After a lengthy private dinner with Xi at Zhongnanhai — the walled leadership compound at the heart of the capital — Obama's aides expected to hear that the two leaders had sparred over contentious issues such as the South China Sea.

'In fact, they had a long conversation about the compatibility between individualist societies and Confucian collectivist ones,' said Rhodes, Obama's former adviser.

What I observed at yesterday's summit was not simply a meeting between two leaders.

It was a portrait of two irreconcilable political temporalities.

The divide between West and China ultimately comes down to this: the unit of time by which each measures its own challenges.

The West is trapped in an endless cycle of electoral cycles and midterm verdicts; China guards and pursues its millennial horizon.