For the better part of the decade, right-wingers in the media have been dogged relentlessly by a pesky fact-checker who has caught them over and over again willfully distorting and fabricating their news.

Fox News has been the special target of David Brock and his minions at the Media Matters for America non-profit based in Washington, D.C., and it’s obvious why. If Fox was bad before, since the election of President Obama the network has become even more propagandistic and morally destitute than ever.

In a report released this week, entitled “Time and Again, Fox News Doctors Video to Smear Progressives,” Media Matters provides damning documentation of ways in which the Fox gang consciously twists the facts to their own rightwing ends.

It’s hard to imagine why anyone, even arch-conservatives opposing the Obama administration, would want to have to rely on information that is simply false. This can hardly help their cause, because it exposes them to ridicule and derision once the real facts are brought to light.

On both sides of the political aisle, among the honest ones at least, the adage, “The truth shall set you free,” is presumably held in high regard. Truth is the most infallible weapon. So what’s the point of being systematically fed something less?

Truly, Fox has devolved into little more than a Goebbels-style propaganda machine aimed at deluding the simplistic masses, and is viewed with a certain disdain even by arch-conservatives smart enough to know better.

In its report this week, Media Matters documents cropped video clips of progressives to present remarks taken out of context. For example, it stated, “During the May 1 edition of (Fox’s) Special Report, saying it was a description of how the president hopes his nominee (for Supreme Court) will interpret the law, congressional correspondent Major Garrett aired a clip in which Obama stated, ‘I view that quality of empathy, of understanding and identifying with people’s hopes and struggles as an essential ingredient for arriving at just decisions and outcomes.’

“Garrett then said: ‘That aggravates those who believe justices should follow the Constitution and legislative intent.’ But Garrett omitted the very next sentence, in which Obama stated: ‘I will seek somebody who is dedicated to the rule of law, who honors our constitutional traditions, who respects the integrity of the judicial process and the appropriate limits of the judicial role.'”

This was only one of eight such examples documented in the report about Fox’s willfully distorted coverage of the facts.

Brock is a particularly well-equipped warrior for truth against rightwing deception. He authored the compelling 2002 book, “Blinded by the Right: Confessions of an Ex-Conservative,” where he chronicled his Washington D.C. career from the time he arrived as a rising star in the world of arch-conservative journalists.

Brock cut his teeth in Washington learning all the tricks of the trade of rightwing “demonization,” himself writing vicious attacks on Anita Hill and Hillary Clinton that were not only published as magazine articles, but became books.

The problem for Brock was that, as a closeted gay man, there was only so much hypocrisy and gay-hating he could take from his rightwing colleagues (even as there remain many very-closeted gays in that milieu). The contradiction between his gay identity and rightwing so-called values caused him to develop an acute capacity for a critical examination of the underlying methods and tactics of the right.

By the time he actually broke away, he’d been carefully looking at the movement from the inside with a highly-critical eye for some time.

Having dabbled in the radical fringe for some time myself, I know exactly where Brock was coming from, and why he is so particularly qualified now to do the important work that he does since he founded Media Matters in 2004.

There are a lot of exposes in Brock’s book, and its follow on, his “The Republican Noise Machine,” but it’s very telling that nothing he’s written has been effectively repudiated: according to him, not a single word.