The fourth filter in Chomsky's and Herman's Propaganda Model of the Media is "flak," which is powerful criticism of the media by elites designed to limit the range of acceptable opinion and acceptable sources that are presented in the media.
One particularly dramatic example
of this occurred back in 2003 during the run-up to the second US invasion of Iraq. At that time, Phil Donahue had the top-rated show on MSNBC. Among other things, Donahue would bring on anti-war guests and guests who raised questions and concerns about the actions of the Bush administration. At this time, MSNBC commissioned an internal study to help chart the future course of the network. As reported at the time:
The study went on to claim that Donahue presented a "difficult public face for NBC in a time of war......He seems to delight in presenting guests who are anti-war, anti-Bush and skeptical of the administration's motives." The report went on to outline a possible nightmare scenario where the show becomes "a home for the liberal antiwar agenda at the same time that our competitors are waving the flag at every opportunity."
As a result of this report, MSNBC went ahead and cancelled the show and fired Donahue. In effect, MSNBC cancelled their top-rated show in order to avoid flak for not being perceived as sufficiently pro-American. As a result, the American public was denied to opportunity to hear important anti-war voices and voices skeptical of the Bush administration (voices that ensuing years have proven correct).
To add to this story, one of the people hired by MSNBC in the wake of this firing was former pro wrestler, actor, and former Governor of Minnesota, Jesse "the Body" Ventura. He was signed to a three-year contract, however, once MSNBC discovered that Ventura was anti-war, they basically paid him to do nothing for three-years. This is yet another example that illustrates how the Propaganda Model of the Media helps explain the media environment we find ourselves in.
A similar example can be found in the case of Bill Maher and his show at the time, Politically Incorrect
. That story, along with a recounting of the Donahue story, some other examples, and some implications for today, can be found here