(CNN) President Trump's speech on Tuesday at the United Nations was an intelligent — at times eloquent — presentation of his "America First" worldview. He laid out an approach of pursuing narrow self-interest over broader global ones and privileging unilateral action over multilateral cooperation. But Trump might not recognize that as he withdraws America from these global arenas, the rest of the world is moving on without Washington. Wittingly or not, Trump seems to be hastening the arrival of a post-American world.