Summits between the US and China are tightly choreographed. They are designed to exude positivity and leave little room for mishaps. But as Donald Trump, the US president, and Xi Jinping, his Chinese counterpart, hold their first meeting on Thursday, there is real scope for disappointment or miscalculation.

Should mutual disillusionment result from one of the most important US-China summits in decades, the impact on global trade and security could be considerable. Rarely since Richard Nixon made his landmark visit to China in 1972 have relations between Washington and Beijing been so antagonistic, complex and consequential.

Setting the tone for his two-day encounter with Mr Xi at Mar-a-Lago in Florida, Mr Trump tweeted that the discussions will be “very difficult” because of America’s “job losses” and “massive trade deficits” with China. Incendiary security issues also bedevil the relationship, a fact dramatised on Tuesday by North Korea’s firing of a missile into the Sea of Japan.