Shortly before President Xi Jinping boarded a plane last month to attend a summit in Russia, his office issued an executive order: China’s stock markets must go back up. The massive state-backed share-buying that ensued propped up the markets briefly in mid-July, allowing Mr. Xi to showcase China’s economic might at the summit with emerging-market leaders. In recent weeks, though, share prices have plunged again, taking global markets with them and triggering an international crisis of confidence in Mr. Xi’s stewardship of the world’s second-largest economy. Mr. Xi will project an image of strength when he presides over a World War II Victory Day parade on Thursday featuring fighter jets, ballistic missiles and 12,000 troops—an event China hasn’t marked in such a high-profile way before. Three weeks later, he heads to Washington for a state visit meant to convey China’s parity with the U.S. Yet just as he stages […]