Others have suggested the so-called "liberal media" is driven more by the pursuit of a compelling story, and has helped promote Romney's momentum narrative down the stretch, while overemphasizing the significance of Obama's poor performance in the first presidential debate.
But it's also possible that both candidates have gotten some tough treatment these last couple months. In fact, a new study from Pew's Project for Excellence in Journalism finds that the media has covered both Obama and Romney more negatively than positively since the week of the Republican National Convention in August.
Overall from August 27 through October 21, 19% of stories about Obama studied in a cross section of mainstream media were clearly favorable in tone while 30% were unfavorable and 51% mixed. This is a differential of 11 percentage points between unfavorable and favorable stories.
For Romney, 15% of the stories studied were favorable, 38% were unfavorable and 47% were mixed—a differential toward negative stories of 23 points.
Obama's coverage "changed almost overnight" following the first presidential debate on Oct. 3, according to the study, with just 13 percent of stories considered favorable in the weeks that followed.
PEJ conducted the study of 52 outlets across media platforms using its in-house human coding system for tone of coverage, while relying on computer software developed by Crimson Hexagon to analyze analyze millions of posts on social media. In an April study, PEJ found Romney to be receiving more favorable coverage than Obama as the Republican primary looked all but over.
Campaign reporters, unlike certain TV hosts, were never quite as enthralled with Obama on ideological grounds in 2008 as is often claimed. But many reporters were attracted to the 2008 narrative surrounding Obama and the history-making nature of his campaign. As a result, overall coverage was far more positive for Obama four years ago, when he was running as a first-term senator, than now, when he's an incumbent president with a record in office.
In that race, Obama’s coverage was almost twice as positive as it has been this year (36% vs. 19%) and more positive than negative overall (36% positive vs. 29% negative that year). McCain’s coverage four years ago, by contrast, was much more negative than Romney’s this year. In 2008, nearly six in 10 stories about McCain were clearly negative in nature (57%), while only 14% were positive.
In addition to traditional media, PEJ studied social media and found one platform where the president had an advantate. The Twitter conversation, PEJ found, "has consistently been harsher for Romney than for Obama."
And the ideological leanings of two cable news networks came through in the study, which found that "71% of the [MSNBC] segments studied about Romney were negative in nature, compared with just 3% that were positive -- a ratio of roughly 23-to-1." On Fox News, 46% of Obama segments were negative, with only 6% positive.
Read the full study here.
ALSO ON HUFFPOST:
How will Donald Trump’s first 100 days impact YOU? Subscribe, choose the community that you most identify with or want to learn more about and we’ll send you the news that matters most once a week throughout Trump’s first 100 days in office. Learn more