From his high-profile address to the UN General Assembly to his high-stakes White House summit with Chinese leader Xi Jinping, US President Donald Trump this week was looking to reassert himself on the world stage.But Trump’s diplomatic flurry has done little to dispel the view among many analysts of a president beset by problems at home and abroad. Those include a widening Iran war that has driven up US gasoline prices and cratered his approval ratings, while his relations with allies worsen a...