It’s an unpopular job, but somebody has to do it.

The role of the debate moderator has faced far more criticism this year than in presidential elections past, with some political pundits attributing the increased scrutiny to the explosion of social media over the last four years -- which has fostered an environment in which every armchair critic in the country has a public soapbox.

On Monday night, the final debate between Barack Obama and Mitt Romney will be moderated by the veteran TV journalist Bob Schieffer. Reporting on the event, the Associated Press referred to the moderator’s job as a “thankless” one, and judging from reactions to Schieffer’s three predecessors, few descriptions could be more accurate. Jim Lehrer was chided for being too inert, Martha Raddatz, too chummy, and Candy Crowley, too aggressive. But while they each brought their own distinct moderating style to a decidedly difficult task, all of this year’s moderators shared one thing in common: They were all criticized for being too liberal by right-wing conservatives.

Now it’s Schieffer’s turn. And when the longtime host of CBS’s “Face the Nation” steps up to the plate at Lynn University in Boca Raton, Fla., Monday night, he can be sure that his every action -- and every word -- will be dissected to death by conservative pundits looking for the smallest hint of favoritism toward President Obama.

Indeed, the 75-year-old Schieffer has already been derided by the usual suspects. NewsBusters’ Rich Noyes on Monday cherry-picked several moments from Schieffer’s moderating and reporting history, remarking on what Noyes perceived as instances of left-leaning bias. (For example, during one of the debates between George W. Bush and John Kerry in 2004, Schieffer mentioned the widening gap between the rich and the poor, which Noyes positioned as a “standard liberal cause.”)   

Noyes did not mention that Schieffer and former President Bush are personal friends who played golf together in the 1990s, or that Schieffer graduated from Texas Christian University, or that Schieffer has publicly criticized the Obama campaign for its constant condemnation of Romney’s private equity record. Instead we heard the usual battle cry: Schieffer is a member of the mainstream media with a default liberal agenda. Never mind that this past summer he compared Democrat Harry Reid to Joseph McCarthy after Reid’s outlandish statement that Mitt Romney hasn’t paid taxes in 10 years, and earlier on Monday, none other than New York magazine’s Daily Intel blog offered a bulleted list featuring “evidence” of Schieffer’s conservative bias.

Admittedly, though, Schieffer has displayed plenty of left-leaning proclivities during his career as well, including a 1990 book that criticized the presidency of Ronald Reagan. The reality is that while journalists will always be taken to task when they allow glimpses of their personal views to peek through their coverage, Schieffer is from a generation of reporters who were taught to strive for objectivity -- far more so than the crop of journalist-activists weaned on Fox News and MSNBC. He earned his first professional accolades as a young reporter for Fort Worth Star-Telegram, shortly after the assassination of John F. Kennedy. (He gave Lee Harvey Oswald’s mother, Marguerite, a ride to the Dallas police station and managed to pose as a detective in the process.) Schieffer has been with CBS News since 1969 and has been the host of “Face the Nation” since 1991.  Like Jim Lehrer, he is stepping up to the plate with plenty of debate-moderating experience, having served as the final moderator for the last two presidential elections.

Also like Lehrer -- and Raddatz and Crowley before him -- Schieffer is brave enough to jump into a no-win situation in which widespread criticism goes with the territory. As Lehrer told Politico this month, “In 2012, there is no way for any moderator to walk through these briar patches without getting stuck. As good as Schieffer is, somebody isn’t going to like him, and they’ll beat him up.”

The third and final presidential debate will air live, 9:00 - 10:30 p.m., EST, from Lynn University in Boca Raton, Fla. The topic will be foreign policy.