IF ANDREW BREITBART hadn't already been exposed as a hack, maybe you could understand how his slander of Shirley Sherrod could get such traction.

He is one of those slugs who emerges from the swamps every few years, passing themselves off as journalists and working to discredit perceived enemies with half-truths, innuendos and outright lies. He is a wholly owned subsidiary of the conservative movement, as are his Web tools, Breitbart.com and Biggovernment.com.

He is not a prostitute. He's much more dangerous than that. He is a zealot so waterlogged on the conservative Kool-Aid that he has come to believe anything goes in the furtherance of his faith.

There have always been propagandists on both sides of every issue. But they can operate with impunity in cyberspace. They keep score by counting page views. For them, truth is quantitative.

But Breitbart is a special case. He is like the emperor who still gets compliments on his new clothes even after his bare butt is exposed.

He was exposed months ago when a hoax perpetrated by his minions, Hannah Giles and James O'Keefe, unraveled. This pair claimed they were dressed like a pimp and prostitute when "officials" in ACORN offices advised them on how to open a brothel that transported sex slaves across the U.S. border.

Breitbart, who employs O'Keefe, presented the heavily edited fiction on his Web sites. Later, when it was revealed that the pair had never actually dressed that way in the ACORN offices they visited, Breitbart stuck to his guns.

Even after attorneys general in New York, Massachusetts and California discredited the tapes, Breitbart insisted they were "essentially" true.

He failed to acknowledge that ACORN workers in San Diego and Philadelphia had called the cops to report the alleged pimp or that of the eight offices they visited, the Baltimore office was the only one where an ACORN worker could even arguably be said to have believed and aided in the alleged pimp tale.

When confronted with the falsehoods, Breitbart claimed he didn't know the tapes had been edited, which makes him either a dupe or a liar. You choose.

But in choosing, consider what he said in a blog posting about his tactics.

He claims his "strategy and tactics were built around my understanding that the mainstream media would be the enemy of the truth and that we would have to go to extreme measures."

Now, fast-forward to Monday, when the furor over the supposedly racist statements of former USDA official Shirley Sherrod hit his fans. Breitbart presented a brief tape purportedly showing Sherrod bragging to a receptive NAACP audience that she had denied help to a farmer because he was white.

But the unedited tape shows Sherrod explaining how her encounter with the white farmer in 1986 taught her that she should help poor farmers regardless of race. Her point was to urge people to rise above race.

This was confirmed Wednesday by Roger and Eloise Spooner, the white farmers who say that Sherrod, then working for a nonprofit, went out of her way to help them stave off bankruptcy in 1986.

But the lie had done its damage. Fox News presented the story unchecked on its Web site and evening news shows. Other Web sites ran with it. The lie became truth by repetition.

Fewer than 12 hours after it broke on Breitbart's site, Agriculture Secretary Tom Vilsack fired Sherrod.

All of this based on a heavily edited video presented by a certified hack who has a record of using heavily edited videos to spread pernicious lies.

The Obama administration is so scared of right-wing charges of racism that they shoot first and ask questions later. NAACP Executive Director Ben Jealous was so spooked, he issued a statement condemning Sherrod even though he could easily have seen the full speech, which was NAACP property.

They're all apologizing now. Vilsack has even offered Sherrod a better job. The president called to chat. Even Fox News' Bill O'Reilly halfway apologized.

But Andrew the Zealot is still keeping the faith. His 37-word correction was heavy on mea and short on the culpa. He had accomplished his real mission, he bragged, by charging the NAACP with racism.

As he told conservative pundit Sean Hannity yesterday, "I could care less about Shirley Sherrod, to be honest with you."

For once, he was.

Send e-mail to smithel@phillynews.com or call 215-854-2512. For recent columns: http://go.philly.com/smith