This is not just happening on the fringes. Our package this week also contains an essay by James Bennet, our Lexington columnist, a former editorial-page editor of the New York Times who was fired for publishing a piece by a Republican senator that sparked a newsroom revolt. He argues that the Times increasingly affirms its readers’ leftish bias even as it reassures them that it is independent. Unlike the right-wing media, the mainstream lot do not routinely peddle falsehoods or conspiracy theories. But their bias undermines their ability to put the record straight. They used to be like the best public broadcasters in other Western democracies, establishing common facts and setting the boundaries for debate; today, less so.
Why does this matter? Although most Americans do not regularly read a newspaper or watch cable news, elites matter in democracies. When different political camps exist in separate information universes, they tend to demonise each other. If you are told Joe Biden is in the grip of a cabal of antisemitic socialists, then voting for Mr Trump makes perfect sense. If Trump supporters are anti-democratic racists, why bother trying to win them over? As a result, the parties will find it even harder to reach the compromises that are essential for sustained good government. If the elites cannot see the world as it is, they will make bad decisions.