Over the weekend, a media micro-controversy broke out: CBS News political director and Slate reporter John Dickerson wrote in an email that he’d rather book a guest other than Michele Bachmann for an online show after Saturday’s GOP debate, of which CBS was a co-sponsor, on the grounds that Bachmann was struggling in the polls and was unlikely to be asked many questions at the debate. By mistake, Dickerson sent the email to a Bachmann aide. Before long, Bachmann’s campaign was flaunting the email as evidence of “liberal mainstream media elites… purposely suppressing our conservative message.”

Two points about this: First, there’s a good case that the media, by freezing Bachmann out, contributed to her fall from her post-Ames high. But it wasn’t the liberal elites what done it. In September, The New Republic published a fascinating piece by Walter Shapiro, who watched 50 hours of Fox News programming during late August. (It’s now behind a paywall.) This was on the heels of a period during which The New Yorker and Newsweek were writing prominent articles about Bachmann, and Jonathan Chait, then of The New Republic, was cranking out blog posts warning liberals to take Bachmann seriously. Given her prominence at the time, and her recent win at the Iowa Straw Poll, Shapiro wrote that he was “braced for a bacchanalia of Michele Bachmann coverage.” Instead, he found:

Without a major gaffe or gotcha moment, Bachmann was almost entirely absent, like a Red Army general excised from the Great Soviet Encyclopedia after being purged by Joseph Stalin. She was almost never pictured on screen, even though she was on a four-day campaign swing through Florida. When her name came up, it was usually coupled with a glib dismissal of her chances….

With hours of air time to fill, there was no reason for the network to prematurely airbrush Bachmann out of the picture, but that’s exactly what happened. Did this have an effect? Possibly. A Fox News poll at the end of my viewing period showed her with just 4 percent support, her weakest showing since early June. That poll then cemented the new Bachmann-is-irrelevant story line.

Given the deep affiliation between Fox News and the GOP, this is a textbook case of the party deciding—in this case, deciding that despite the excitement she was generating, Bachmann wasn’t a top-tier candidate. It’s become a reflex for conservative politicians to complain about their treatment by the “liberal media,” but Bachmann’s grievances are better directed at the home team.

The second point is that of course media outlets want to focus their attention on front-running candidates who are attracting voters’ (and viewers’, and readers’) attention; Dickerson, to his credit, hasn’t run away from this obvious truth. In part, that’s due to base commercial incentives: Newsweek put Bachmann on the cover with an inflammatory “crazy-eyes” photo back in August, around the time she was peaking, because it thought it would sell magazines that way. It’s the same reason Tina Brown ordered up a creepy photo illustration of “Diana at 50” a few weeks earlier.

But there are also good democratic reasons for the media to focus on candidates who are competitive in the horse race, especially once a few laps have been run. Republican elites, and Republican voters, are trying to figure out who their presidential nominee will be. They have a need for information, which the press can help provide, about candidates who are serious contenders. But once both polls and other indicators suggest the party has made a decision that a particular candidate isn’t a serious contender, where’s the benefit in the press pretending otherwise? Why should reporters cover the race as if Michele Bachmann or Ron Paul or Rick Santorum might win, when the party has pretty much made clear they won’t?

Greg Marx is a CJR staff writer. Follow him on Twitter @gregamarx.