Responding to my last column, Eric Alterman says the reason the media obsessed over Barack Obama's ties to William Ayers while ignoring John McCain's relationship with Gordon Liddy is that McCain raised Ayers and Obama did not raise Liddy -- even though the recent media frenzy around Ayers began not with a McCain attack, but with a 2,100-word front-page New York Times article:

Liddy is not an issue because Obama never raised it; Ayers is an issue only because McCain did. The inverse to Foser's question: do you think the media would have found an education board Obama served on years ago, and tied him to the 40-year-old radical history of one of his many colleagues on that board, all on its own? After having been aware of the tangential relationship for many months, would the MSM have raised the issue and gone wall-to-wall with coverage in October 2008, weeks before the election, without the Republican Party pressing the issue? You know the answer.

That's a common explanation for disparate coverage of seemingly analogous situations, but I don't buy it.

The basic problem is that the theory relies on circular logic. How do you explain the disparate coverage of Ayers and Liddy? The Republicans are pushing the Ayers story and the Democrats aren't pushing Liddy. Well, how do you know the Democrats aren't pushing Liddy? Because the media isn't covering him as much as they're covering Ayers.

In this case, the assumption that Democrats haven't urged reporters to cover Liddy is shaky at best. The DNC hit McCain for his ties to Liddy in a press release as long ago as May. And they were promptly ignored. And others have brought up Liddy -- including Media Matters, repeatedly, in pointing out the double-standard the media was applying. More importantly: we don't know what people are doing behind the scenes. You can assume no one has been urging reporters to cover Liddy if you want; I think the much more realistic assumption is that some people are doing so.*

More broadly: Over the past several weeks, the media has swarmed to cover several McCain attacks - “lipstick on a pig,” Ayers, ACORN, “Joe the Plumber,” and more. All of those attacks got considerable coverage, driving the media's coverage of the campaign for days at a time. I can't think of a single Obama campaign attack that the media has rushed to repeat over and over again in the same way. It isn't that the Obama campaign isn't criticizing McCain. It is, every day. But the media hasn't entered feeding frenzy mode around those attacks. That's a blow to the “the media simply covers the campaigns” attacks" theory.

Alterman argues: "[T]he mainstream media frequently allows the campaigns to exercise almost total authority over campaign narratives. ... By ceding narrative and investigatory authority to the campaigns, the mainstream political press is rendering itself useless."

But this doesn't happen uniformly. The media cede far more narrative and investigative authority to Republicans than to Democrats. Even many reporters will acknowledge this - indeed, Alterman provides examples of reporters doing so. But they claim it is because Republicans are simply better at pushing negatives.

This, too, is circular. Who decides what gets coverage? Reporters. Why do reporters give more attention to GOP attacks? The attacks are better. How do reporters know they're better? Their attacks get more coverage.

The Republicans may be a bit better; there's no way to objectively measure that. But the gap certainly isn't large enough to explain the disparate coverage. If the media was really equally responsive to attacks from Democrats and Republicans, it wouldn't take the world's greatest political operative to sell a story as simple as “John McCain said he was 'proud' of a guy who plotted the murder of a journalist and urged people to shoot law enforcement agents in the head.”

To be clear: I am not saying that disparate efforts by the campaigns (and others) to push the Ayers and Liddy stories have played no role in the disparate coverage those stories have gotten. I'm saying that is only one factor, and probably not the most significant factor.

* Sure, some will say: “But the Democrats aren't talking about Liddy publicly.” First, enough people have invoked him publicly over the past few months - including a DNC press release - to cast doubt on that explanation. But more importantly: campaigns, party committees, and others push stories to reporters on background all the time. But if you insist that such things don't count, then how do you explain that 2,100 word front-page New York Times article about Ayers? Either GOPers working on background urged the Times to write it, in which case Democratic behind-the-scenes efforts to get reporters to cover Liddy count. Or the Times came up with the Liddy story completely on its own, which fatally undermines the “reporters just cover campaign attacks” theory.