US President Donald Trump’s landmark visit to China comes as the Iran war disrupts global energy supplies, fuels economic uncertainty and adds fresh strain to Washington-Beijing ties. In the latest part of a series examining how rivalry, interdependence and geopolitical crises are reshaping the relationship between the two powers, we look at how Trump’s weakened hand could tilt summit talks. When next week’s summit between US President Donald Trump and Chinese President Xi Jinping was first...