A more thorough explanation:

The equal-time doctrine, also known as the fairness doctrine, was a rule established by the Federal Communications Commission (FCC) that required broadcast media to provide a reasonable opportunity for discussion of conflicting views on issues of public importance.

For example, if a radio station aired an interview with a political candidate, they were required to offer the same amount of airtime to their opponent. This ensured that all sides of an issue were presented fairly and that the public had access to a variety of viewpoints.

The FCC abandoned the fairness doctrine in 1987, which led to the rise of talk radio and cable news programs that often present a biased or one-sided perspective. Some people argue that the lack of a fairness doctrine has contributed to the polarization of American politics.