By: Guest ContributorApr. 28th, 2011more from Guest Contributor

According to the Pew Research Center’s Project for Excellence in Journalism, MSNBC devoted the most airtime to debunking the Obama birther conspiracy last week. MSNBC’s devoted more airtime to the story than any other cable network, and spent more time debunking the story than their cable news competition.

Here are the numbers from PEJ via the Poynter Institute’s Julie Moos:

MSNBC

Including “The Ed Show,” “Hardball,” “The Last Word,” and “The Rachel Maddow Show”

28% of airtime studied was devoted to the 2012 election
10% of airtime studied was devoted to Obama
A subset of that Obama airtime was coded “citizenship and religion rumors” to include “birther” coverage, which was 92% of the Obama coverage

Fox

Including “Special Report w/Bret Baier,” “Fox Report w/Shepard Smith,” “The O’Reilly Factor,” “Hannity”

16% of airtime studied was devoted to 2012 election
5% of airtime studied was devoted to Obama
A subset of that Obama airtime was coded “citizenship and religion rumors” to include “birther” coverage, which was 8% of the Obama coverage

CNN
Including “The Situation Room,” “John King, USA,” “In The Arena,” and “Anderson Cooper 360″

11% of airtime studied was devoted to 2012 election
5% of airtime studied was devoted to Obama
A subset of that Obama airtime was coded “citizenship and religion rumors” to include “birther” coverage, which was 100% of the Obama coverage.

The numbers are skewed towards MSNBC, because Pew’s Excellence In Journalism project has consistently found MSNBC devotes more airtime to politics that the other cable networks. In case you are curious CNN covers politics the least. MSNBC was spending their airtime debunking the birther conspiracy, but they still covered the story more than anyone else.

The question is does coverage of a conspiracy theory legitimize an illegitimate question like those that were raised about Obama’s birth certificate? Maybe, but MSNBC did not do what the other networks did. They did not host birthers on their programming and let their claims go unchallenged.

Media Matters found that 84% of the birther claims in the most recent 52 segments on the subject on Fox News went unchallenged. On the issue of birther coverage, we have MSNBC debunking the conspiracy, Fox News enabling it, and CNN was not paying much attention to it at all.

I personally think that since there were so few people in the mainstream media who were willing to stand up for the truth on this birther story, the MSNBC hosts, ABC’s George Stephanopoulos, CNN’s Anderson Cooper, and Fox News’ Shep Smith are the exceptions, MSNBC had to devote lots of airtime to it.

The mainstream media negligently ignored the birther conspiracy theory for over 3 years. It took Donald Trump’s endless huckstering and carnival barking about Obama’s birth certificate to get the media to pay attention, and when they did pay attention the vast majority of them didn’t want to be bothered with the facts, because they have a Trump 2012 storyline to sell.

Fox News pushed the birther conspiracy. Since CNN doesn’t do much with politics, except hire more right wing pundits and jump in bed with the Tea Party Express, MSNBC became the last line of defense for the truth.

Regardless of the political advantages to the timing of President Obama releasing his birth certificate, the White House realized that they couldn’t count on 90% of the mainstream media to report the facts, so he had to set the record straight once and for all themselves.

If the majority of the media would have done its job as the Fourth Estate, yesterday’s long form release would have never happened.

Here is a scary thought. Without MSNBC to balance the ongoing conservative media bias on this story, who knows how many more Americans might have believed that a baseless conspiracy theory was a legitimate political issue?

Watch the coverage from last week, MSNBC prime time did not do a single unchallenged or pro-birther story. The astounding fact is that MSNBC was the only cable news network to consistently debunk the conspiracy theory.

MSNBC leaned forward and got this one right.