Conservatives have long known that the mainstream media sees -- and then tells the rest of us about -- the world through a filter of liberal bias. After all, not only do conservatives read the bias in the morning newspaper and hear the bias on the evening news, but also survey after survey has shown that our nation’s newsrooms are filled with self-identified liberals and registered Democrats. In other words, the media’s liberal bias isn’t news, it’s just reality.

Correction: The media’s liberal bias isn’t news for the rest of us. But for the mainstream media, their own liberal bias certainly is news -- headline grabbing, discussion provoking, breaking news. And, this past week, the media became acutely aware of that bias and began reporting it -- not to mention illustrating it.

The lead media bias story came across the Associated Press wires to start the week. The piece began anecdotally by noting that all three network news anchors would be taking their evening newscasts on the road this week “to meet Barack Obama during [his] overseas trip.” But the story did not limit itself to illustrative examples of left-leaning media favoritism, it also laid out hard numbers. Indeed, just three paragraphs into the piece, the reporter explained that presumptive Democratic presidential nominee Barack Obama had been consistently getting far more media coverage then his Republican counterpart John McCain. Thus, the story asked in its suggested headline: “Is media playing fair in campaign coverage?”

The reporter cited studies done by the Project for Excellence in Journalism (PEJ), which demonstrated that, in the weeks since the race for the White House has become a two man contest, Obama played a significant role in 78% of all stories studied, while McCain played a similarly prominent role in just 51% of those same news items. In the study, the PEJ -- funded by the Pew Charitable Trusts -- analyzed hundreds of stories to determine whether one or both of the presidential candidates had a “significant presence,” defined as “25% of the story must be about that person.”

So, over the past month-and-a-half, in the news stories that mattered, the mainstream media wrote or talked about Democratic nominee Obama more often than Republican nominee McCain by more than 27%. Furthermore, according to the PEJ, this wide media gap has been a consistent phenomenon, with the “closest” the candidates have been in any week’s “coverage” coming in “the week of June 30 through July 6, when Obama enjoyed an 11 percentage point advantage.”

On the day the Associated Press story appeared in newspapers and online, the Drudge Report broke a story that perfectly illustrated the media’s liberal bias that had just been confirmed by the PEJ’s hard research. Specifically, Drudge reported that “[a]n editorial written by Republican presidential hopeful McCain has been rejected by the New York Times -- less than a week after the paper published an essay by Obama.” What’s more, Drudge explained that the Times’ op-ed page editor told McCain’s staff that the piece was unacceptable “as currently written,” but that “[i]t would be terrific to have an article from Senator McCain that mirrors Senator Obama’s piece.”

The op-ed page editor told McCain staffer Michael Goldfarb that, to appear in the Times, a McCain “article would have to articulate, in concrete terms, how Senator McCain defines victory in Iraq.” The e-mail further instructed that the piece “would also have to lay out a clear plan for achieving victory -- with troop levels, timetables and measure for compelling the Iraqis to cooperate” -- never mind that McCain’s consistent position has been an continues to be that such “timetables” couldn’t and shouldn’t be established. The Times’ position was that if McCain wanted an op-ed published, it must conform to how the Times -- and not how McCain -- sees the world.

In so doing, the Times provided a clear example of the liberal media bias that is part and parcel of the mainstream news coverage. After all, here was the country’s leading newspaper, whose motto is “All the News That’s Fit to Print,” deciding that an op-ed by the presumptive Republican presidential nominee did not qualify “as currently written” as “News That’s Fit to Print.” Moreover, that the Times rejected McCain’s op-ed despite the fact that the newspaper had just printed an op-ed by his opponent not only on the very same topic, but also that specifically attacked McCain, reinforced the point that blatant bias was at work.

As it turned out, McCain probably got more coverage for his op-ed response to Obama through the ensuing controversy than McCain would have if the Times had simply accepted the piece and run it. But that was just for the one story, and, as the hard research has now shown, liberal media bias is including Obama and excluding McCain in countless other stories.