A burst of interest in the phrase “Thucydides Trap” followed Xi Jinping’s closely watched meeting with US President Donald Trump in Beijing on Thursday, after China’s leader invoked the concept during talks that also touched on issues as contemporary as artificial intelligence and advanced computer chips. For many readers, the immediate question was obvious: why was an ancient Greek historian suddenly at the center of a summit about 21st-century rivalry? The term was popularized in 2011 by US political scientist Graham…