Seeing the Forest: Colbert Affair Exposes Loss of Rights:
In 1987 Ronald Reagan ordered the FCC to abolish the Fairness Doctrine, which required broadcast media to provide balanced coverage of issues. Majorities in the Congress voted to restore the Fairness Doctrine and were blocked by Republican vetoes and filibusters. (Any time you hear a Republican complain about the "liberal media" ask them why it is Republicans, not Democrats, who oppose the Fairness Doctrine.) Following that, Republicans began to allow fewer and fewer large corporations to control more and more of these information channels. (PLEASE click the links. More here and here.)
Before these changes you would see representatives of Labor, Democrats, anti-war, religions other than far-right Christianity, and other now-banned viewpoints. One particular viewpoint you would see expressed was a concern that concentrated corporate ownership of the channels of information would harm democracy. That viewpoint is also banned now.