The right has been fulminating for decades about liberal bias in the media. More recently the left, including Bernie Sanders, has inveighed against capitalist bias caused by corporate ownership of news organizations.

Meanwhile, a quarter-century covering national politics has convinced me that the more pervasive force shaping coverage of Washington and elections is what might be thought of as centrist bias, flowing from reporters and sources alike. It is a headwind for Warren, Sanders, the “squad” on Capitol Hill, even for Trump. This bias is marked by an instinctual suspicion of anything suggesting ideological zealotry, an admiration for difference-splitting, a conviction that politics should be a tidier and more rational process than it usually is.

A confession: I’ve got it. A pretty strong bout, actually.