American global leadership is ending. Not because of “American decline,” or the emergence of a multipolar world, or the actions of U.S. adversaries. It’s ending because President Donald Trump wants to end it. Just about all of Trump’s policies, both at home and abroad, are rapidly destroying the foundation of American power. The main beneficiary will be the Chinese leader Xi Jinping, who has been planning for the moment when Washington stumbles and allows China to replace the United States as the world’s superpower. That Trump is willing to hand the world over to Xi.