An economist who won the Bates Award, which is given to a promising economist under age 40, published a study which explains the source of bias in the media. Samuelson summarizes the study and I cannot detect the conservative bias that is common to the op-eds that he publishes in the Washington Post. Maybe is need to take a closer look, but the study makes sense. It argues that the media do what most businesses do. They try to make a profit. That means building a large audience that attracts advertisers and revenues.
The study found that the bias found in the media reflect biases held by their target market. The media understands their target market and they give them the slant on the news that they want. Major media outlets, like the Washington Post serve a very large and diverse market. That probably explains why the Washington Post provides a platform for conservatives like Samuelson and George Will, who write for the their audience, as well as couple of liberals. The New York Times plays a similar game by giving us Paul Krugman and David Brooks. Cable news plays the same game. MSNBC targets a liberal audience and Fox News has helped to build its conservative audience by feeding it a steady diet.