Some politicians use the media to their advantage. Others reshape it in their image.Had the political force that is Donald J. Trump met the immovable object that was the American news media in the 20th century, the result would have been predictable. Trump would have vanished without a trace, along with such wannabes and also-rans as Edmund Muskie, Howard Dean, Gary Hart and John Edwards. Today, however, the once-powerful Fourth Estate might as well...