Last week, blogger Andrew Breitbart released a mischievously edited video. It showed a black Department of Agriculture official, Shirley Sherrod, recalling her seemingly racist reluctance to assist a white farmer more than two decades earlier. Some in the audience of NAACP members are heard engaging in a sort of call-and-response approval of Sherrod's sentiments. Reacting to the edited video, Sherrod's boss, Agriculture Secretary Tom Vilsack, demanded her resignation.

Now imagine if it had gone a little differently - if, before Sherrod could resign, the White House had intervened and saved her job. Imagine the reaction of those now trying to put President Obama at the center of this debacle by blaming him for Sherrod's unnecessary resignation. They would have been outraged if he had backed her up in the face of the initial information.

Should Vilsack have investigated further? Yes. Ditto for the NAACP. But White House spokesman Robert Gibbs should not have been the first to offer Sherrod an apology. It should have been Breitbart, the man who started the controversy. What he did was tantamount to releasing the Zapruder film minus the moment of impact.

Breitbart's explanation - that he didn't realize the video had been so maliciously manipulated - only amplifies his irresponsibility. Of the "source" who gave him the video, he told the Daily Beast: "I don't know this person. I can't divine what that person's motivation was. I don't know."

A little less trust and a little more verify next time, Mr. Breitbart.

Even shallower was Breitbart's description of his own motivation: "The video shows racism, and when the NAACP is going to charge the tea party with racism . . . I'm going to show you it happens on the other side."

Even if you take that bogus explanation at face value, Breitbart at least should have highlighted the fact that the NAACP audience also expressed approval when Sherrod brought her story full circle and said poor people of every race need help. But he didn't.

Such are the pitfalls of a media world in which everyone plays whisper-down-the-lane, but nobody fact-checks the message.

The reality is that the audience's reaction was not a tacit approval of Sherrod's momentary reluctance to help a poor white farmer. Rather, it was the kind of response you might hear when any engaging story is told in an African American church. Any remotely honest observer who watches Sherrod's full speech must acknowledge that the audience was rooting for her ultimate redemption - not applauding her outdated shortcomings.

Too bad everyone - including Breitbart, his loyal readers, the media, the NAACP, and the Department of Agriculture - was willing to accept the video at face value. To fully understand why they did, a little context is in order.

First, in the polarized media world we live in, Breitbart enjoys credibility he does not deserve. The only credential required to cast oneself as a media player today is a partisan one. If you are willing to conform to the artificial extremes of left/right, liberal/conservative, and blue/red, you get a keyboard or a microphone and, voilà, you are in business!

Some of those bearing such credentials have conditioned their audiences to believe that Obama is a racist. Glenn Beck has said the president has "a deep-seated hatred for white people or the white culture." Rush Limbaugh called the commander in chief "the greatest living example of a reverse racist" after his Supreme Court nomination of Sonia Sotomayor, herself an alleged "reverse racist" and "hack." Newt Gingrich, who also called Sotomayor the R-word before walking the comment back, charged that Sherrod showed a "viciously racist" attitude.

All the false charges of racism condition these talking heads' followers to readily accept that a minority woman speaking any ill of white farmers must be racist, without even pausing to wonder if there could be more to the story.

Which is not to say there isn't plenty of blame to go around. Vilsack and the NAACP should have reserved judgment, especially if Sherrod was telling them that Breitbart's clip was part of a longer speech with a different message (which, presumably, she was). The news outlets that ran with the clip also should have done more to determine whether it was authentic.

The only mistake the White House made was in failing to tune out Breitbart, the same "journalist" who lent his heft to a guy later charged in a plot to tamper with phones in the office of Sen. Mary Landrieu (D., La.).

The administration would have been better off remembering the words then-Sen. Obama spoke in the midst of another racial kerfuffle: "The profound mistake of Rev. Wright's sermons is not that he spoke about racism in our society," Obama said at the National Constitution Center. "It's that he spoke as if our society was static; as if no progress has been made. . . . But what we know - what we have seen - is that America can change. That is [the] true genius of this nation."

We should have known right away that Shirley Sherrod was making the same point. For missing it, Tom Vilsack owed her the apology he offered. For obscuring it, Andrew Breitbart owes the rest of us one as well.