Media Matters founder David Brock wrote in an April 8 “Comment is free” post on the website of the U.K.'s Guardian newspaper:

This week, we heard the welcome -- and overdue -- news that toxic host Glenn Beck will be leaving his Fox News programme later this year.

It shouldn't have taken so long for News Corp to realise that Beck was bad for business -- that a million lost viewers, more than 300 lost advertisers and widespread criticism all added up to a disastrous business model. And it should have been clear from the moment in 2009 that Beck called President Obama a “racist” who “has a deep-seated hatred for white people or the white culture” that he wasn't an appropriate host for a responsible journalistic outlet to put on the air.

But Fox News is not a responsible journalistic outlet, and we shouldn't think for a minute that Beck's departure means Fox News has suddenly embraced accountability and restored credibility. One of the biggest of the many falsehoods repeatedly pushed on the network is not about any specific policy issue, but about Fox News itself: the continued insistence that the network is a “fair and balanced” source of news.

The truth is that, even without Beck's hour of hate, lies, extremism and paranoia, Fox News will remain a Republican political operation masquerading as a news network. Its executives and personalities insist there's a clear line between its “straight news” programming and its “opinion” programming. But the research and investigation we've done have shown that claim to be laughably hollow.

Those looking to see how the “straight news” portion of Fox's programming works need look no further than Fox News's DC managing editor, Bill Sammon. In numerous emails leaked to Media Matters for America, Sammon has passed down the order to slant news coverage of Barack Obama and of issues like healthcare, the environment and the Middle East.

In audio uncovered by Media Matters, Sammon let slip his lack of journalistic ethics to attendees on a high-priced cruise for donors to a conservative college. In front of the friendly crowd, here's how Sammon gloated about pushing lies about Obama on air:

“Last year, candidate Barack Obama stood on a sidewalk in Toledo, Ohio, and first let it slip to Joe the Plumber that he wanted to, quote, 'spread the wealth around.' At that time, I have to admit, that I went on TV on Fox News and publicly engaged in what I guess was some rather mischievous speculation about whether Barack Obama really advocated socialism, a premise that privately I found rather far-fetched.”

The effort to push this lie wasn't just a passing fancy for Sammon: he sent an internal email to Fox News staff pressuring them to push it, and Fox employees responded by linking Obama to socialism on air 35 times in the final days before the 2008 election.

Sammon, an ideologue who has hosted fundraisers for conservative candidates, drives the network's “news” coverage. And the evidence shows he asks his “news” staff to cast doubt on climate science, use poll-tested GOP language to talk about policy and promote attacks on President Obama. And Fox has made no effort to hold Sammon accountable. That's because, for Fox News, promoting political smears instead of truth is a feature, not a bug.

If Fox's spread of misinformation is prescribed at the institutional level, it is also contagious from Beck to other hosts: Beck's brand of extremism runs through the network. Numerous Fox personalities, including Sean Hannity and Sammon, have, like Beck, insisted that the president has a problem with race. Beyond Beck, the network has spread race-baiting conspiracy theories, from attempting to link Obama to the New Black Panther party to the smears of Shirley Sherrod. Recently, Fox has increasingly highlighted delusional, discredited accusations about Obama's birth certificate.

With Beck on his way out, Fox News has a choice to make. Getting rid of one person does not stem the flow of extreme rhetoric, wilful dishonesty, conspiracy theories and outright political attacks from Fox. And as Glenn Beck proves, this behaviour not only harms the institution of journalism, but News Corp's bottom line as well. News Corp learned the hard way with Beck's show that extremism and misinformation are bad for business. Will the company treat this moment as an opportunity to make Fox a responsible news network, or will it continue to ignore any semblance of journalistic integrity, making Beck the first in a line of exits of a flawed business model?