China’s engagement with traditional US allies amid the turmoil of Donald Trump’s presidency may be a sign that it is moving away from its customary diplomatic approach in favour of a “wedge strategy” that some observers believe may help reshape global dynamics. They point to the ways US partners are trying to keep as many doors open as possible – to insure themselves against both an erratic Washington and increasingly assertive Beijing. At Davos last month, Canadian Prime Minister Mark Carney...