If you’ve been wondering why the Coalition, despite its heavy defeat in 2007 and poor standing in the polls, still seems to set the political agenda on topics ranging from refugees to insulation to global warming, a case this week from the United States might provide some hints.

Shirley Sherrod, who was Georgia state director of regional development at the US department of agriculture, lost her job on Monday after right-wing blogger Andrew Breitbart posted a video that appeared to show her admitting to having made decisions based on racial resentment against white farmers (Sherrod is black).

This was all part of a vendetta by Breitbart against the National Association for the Advancement of Colored People, which last week passed a resolution stating what everyone knows but many are afraid to say, that the “Tea Party” movement is deeply permeated by racism.

Breitbart, however, has a history of playing fast and loose with the truth, and sure enough when the unedited version of the Sherrod video surfaced yesterday it conveyed a very different message: Sherrod was telling a story of how she overcame her own racial demons and learned the importance of treating everyone fairly.

Agriculture secretary Tom Vilsack has now admitted to acting wrongly and in haste, and has made a full apology to Sherrod and offered to re-employ her. White House spokesman Robert Gibbs added Barack Obama’s endorsement to the apology, saying Sherrod had been the victim of an “injustice”.

How can something such as this happen? How can a person’s career be ruined on the word of an obviously partisan activist, with no one taking time for reflection or to hear the victim’s side of the story?

Commentators are blaming the relentless nature of the modern 24-hour news cycle, but that’s only part of the story. The beat-ups almost exclusively harm one side of politics. Republican administrations don’t seem to suffer from this sort of casual character assassination, just as Coalition governments here don’t seem to fall victim to the scandal du jour over not actually bungled home insulation schemes.

The point is not that there aren’t unscrupulous bloggers and pundits on the left: obviously there are. But they generally stay on the fringe, whereas those on the right have become mainstream and are given a credibility they don’t deserve.

While the right tends to be willing to tough out public criticism, even in clear cases of wrongdoing, the left has become scared of its own shadow. Hence an accusation of “racism” cost someone her job with no proper investigation, simply for fear of the disapproval of hate merchants whose views are already predetermined.

Let’s hope the Sherrod affair provides a wake-up call to the media here as well as in the US. When one side is at least trying to play by the rules, while the other side recognises no obligation at all to truth or fairness, it’s hard to maintain a level playing field.