Bangladesh, May 22 -- As Xi Jinping and Donald Trump began their much-talked about summit in Beijing on Thursday, the Chinese president announced, in his opening remarks: "The world has come to another crossroads."

He then posed the question: "Can China and the United States transcend the so-called 'Thucydides's trap', and forge a new paradigm for major-power relations?"

Thucydides was an ancient Athenian historian and military commander, who wrote a history of the Peloponnesian War in ancient Greece, a decades long conflict that erupted between Athens and Sparta in 431BC.

In foreign policy commentary, the 'Thucydides's trap' (or simply Thucydides trap) refers to the idea that when a rising power threatens to displace an established on...