Mitt Romney and Paul Ryan were repeatedly accused by the media of making false claims during the Republican national convention.  The reporters didn't just question the accuracy of certain statements as they might have done in years past.  They flatly stated that the assertions were found to be false by the fact checkers.

However, just because someone hangs out a shingle that says "fact checker," that doesn't mean they have a lock on the truth.  Heck, it doesn't even prove that they are credible.  This is particularly true in politics, where facts often mingle with opinions.  Like initial reports about breaking stories, the findings of self-appointed fact checkers should be greeted with skepticism.

It's not terribly surprising that the mainstream media has pounced on the opportunity provided by the fact checkers.  The media's credibility among the American public is at an all-time low.  Most Americans perceive the media as terribly biased.  No doubt, many media figures believe they can boost their credibility-or at least shield themselves from further charges of bias-by hiding behind self-styled fact checkers.

Fact-checking websites use a number of tactics to convince visitors that they are fair and reliable.  They claim to be non-partisan.  They demonstrate their neutrality by criticizing both sides.  They show that they are thorough and nuanced by assessing some claims as partially true and others as partially false.  And they use gimmicks such as the "Truth-O-Meter" to convince people that they are singularly focused on gauging the truth.

Take for instance PolitiFact.com.  This fact-checking website is operated by the Tampa Bay Times, a newspaper widely considered anti-Republican (and known to some as the "Florida Pravda").  However, if a website purports to be fact checker, then shouldn't it be operated by people who can legitimately claim to be impartial?   PolitiFact is staffed by the same old reporters and researchers.

The first thing that anyone visiting PolitiFact.com will notice is that the site appears to be as devoted to criticizing President Obama as it is to criticizing Mitt Romney and Republicans.  However, that impression doesn't hold up under closer inspection.

PolitiFact's homepage features a comparison ("rating their promises") of the GOP leadership and President Obama.  At first glance, both sides have many "broken promises" to explain.  However, the chart suggests that President Obama keeps his promises almost twice as often as Republicans.  Oh well, perhaps that is just the way things are.

Dig deeper, however, and you will find that the explanations are invariably favorable to President Obama.  When PolitiFact says that President Obama broke a promise, it usually means that he was prevented from keeping that promise by Republicans and their allies. 

For example, President Obama promised to create a foreclosure prevention fund; he did, but the big banks failed to cooperate.  President Obama promised to "repeal the Bush tax cuts for higher incomes"; he didn't, but that was a necessary concession in striking a deal to extend middle class tax cuts.  Similar excuses are offered for the rest of what PolitiFact calls Obama's "Top Ten Broken Promises."

While PolitiFact goes out of its way to soften criticism of President Obama, no such understanding is shown toward Mitt Romney.  For example, Mitt Romney's charge that President Obama began his presidency with "an apology tour" is described as an out-and-out "pants-on-fire" lie.  PolitiFact does not dispute that President Obama told foreign audiences that "America has shown arrogance" and "at times we sought to dictate our terms."  Instead, the clearly apologetic remarks are shrugged off as standard "diplomatic language." 

PolitiFact also characterized Mitt Romney's accusation that President Obama gutted the work requirement from welfare (repeated by Rick Santorum) as a "pants-on-fire" lie.   However, the Obama administration issued a directive permitting waivers of what under the 1996 law were mandatory work requirements.  And PolitiFact described as false Paul Ryan's claim that the GM plant in Janesville closed after President Obama took office.  However, two articles (one by the Associated Press) corroborate the assertion that while the plant ceased making large SUVs in late 2008, it continued to operate with a reduced workforce making trucks until mid-2009.  If PolitiFact were sincere about helping "you find the truth in politics," it would not continue to portray these statements as completely false.

PolitiFact is really a propaganda site.  It makes selective use of facts to boost President Obama.  The good news is that while anyone can create a "fact check" website, the Web also makes it easy to double check their work. 

Ira Brodsky is a writer based in St. Louis, Missouri. He blogs at irabrodsky.com.