To protect Americans against “fake” news, Facebook will now use filters so that only “reputable” articles can appear at the top of users’ trending news stories.  And Facebook is going to media fact checkers for help (initially ABC News, The Associated Press, FactCheck.org, Politifact and Snopes). But guess what? These fact checkers have their own biases — usually the same liberal biases that we see in the rest of the mainstream media.

Before the 1990s, the mainstream media had a monopoly on the news.  Then came the rise of talk radio, Fox News, and the internet. This was a wonderful thing for freedom of information.

Facebook has already faced a scandal for having “filtered out stories on conservative topics from conservative sites.” 

But to get an idea of how bias also affects fact checkers, just consider a few evaluations from Politifact.

— "We’re the highest taxed nation in the world. Our businesses pay more taxes than any businesses in the world. That’s why companies are leaving.” Donald Trump on "Meet the Press" on May 8, 2016

Donald Trump was clearly talking about tax rates for businesses.  But in rating the claim as “False,” Politifact focuses on total federal tax burden as a share of GDP. Trump was correct that the U.S. has the world's highest corporate income tax rate (combined federal and state).  In 2016, that rate was 38.9 percent  France came in second with 34.4 percent.  But Politifact conveniently overlooks state taxes, which are really what put the U.S. over the top compared to so many other countries.

— On November 9, California Lt. Governor Gavin Newsom claimed that his state’s gun control laws were responsible for a "56 percent decline in the gun murder rate" since the 1990s.  Politifact rated this statement as only "mostly true,” but only because the drop in murders was even greater than 56 percent between 1993 and 2014.  

Bizarrely, Politifact didn’t question the claim that this drop was due to California’s gun control laws. Pete Wilson, who was the Republican governor from 1991 to 1999, did very little on gun control. 

Probably the only significant new regulation was the 1994 California Gun Free School Zone law, but this didn't even forbid permit holders from carrying on school property.  

The major gun regulations only started after Democrat Gray Davis took office in 1999.  During the first five years of the period Politifact studied when there was little change in gun laws, gun murders fell by 54 percent, over 80 percent the total 67 percent drop between 1993 and 2014.  

Politifact ignores all of the other major crime legislation that was enacted by the Republican governor.  For instance, California passed the 1994 Three Strikes law, which doubled the penalty for a second felony if the first one was serious or violent.  A third felony carried a prison sentence of 25 years to life.  Much research showed that significantly higher criminal penalties likely played a role in reducing crime rates.

— “Of course there is large scale voter fraud happening on and before election day.”  Donald Trump on Monday, October 17th, 2016 in a tweet

Politifact didn’t just say that this claim was false, they deemed it worth the designation: Liar, Liar “Pants on Fire.”  While the term “large scale” fraud might be in the eye of the beholder, voter fraud in 2008 gave Al Franken the Senatorship in Minnesota and even control of entire state legislatures have been determined (e.g., the Pennsylvania state Senate in 1994).  From California to Pennsylvania to Virginia to Indiana, many thousands of illegal aliens, dead people, and just non-existent ones were caught being registered to vote just a month or so before November election.

A 2014 study published in the journal Electoral Studies used survey data to estimate that 6.4 percent of the nation’s non-citizens voted in 2008 — that would be over a million votes.  Another 2012 study from the Pew Center on the States estimated that one out of every eight voter registrations is inaccurate, out-of-date or duplicate, 2.8 million people are registered in more than one state, and 1.8 million registered voters are dead. 

In an undercover video, a New York City Board of Elections member was recently caught complaining about the amount of voter fraud created by New York City mayor Bill de Blasio’s decision to give out ID cards without checking recipients’ identities. 

A similar problem exists in other states, such as California, where illegal aliens are given driver’s licenses and nothing to verify citizenship during voter registration.

To say that vote fraud isn’t common is itself a pretty absurd claim. 

— Compare two statements evaluated by Politifact earlier this year.

"Ninety percent of Americans want our background check system strengthened and expanded to cover more gun sales.” Connecticut Democratic Senator Chris Murphy in a July 27th, 2016 speech at the Democratic National Convention in Philadelphia 

"Everywhere that we have more citizens carrying guns, crime is less.” Texas Lt Governor Dan Patrick on NBC's "Meet the Press", January 3rd, 2016 (Focusing on the part of his statement discussed in the “our ruling” section)

Politifact deemed Murphy’s statement as “True” and Patrick’s as “Mostly False.”  In assessing Patrick’s statement, they noted one pro-carry study by myself but several others that claimed that concealed carry had no effect on crime. 

I was interviewed by Politifact in their evaluation of Patrick’s statement and provided them with a long list of studies, but this list was ignored.  

Politifact characterized my peer-reviewed research as "a disputed study by a gun rights advocate” and indicated that the other research was conducted by academics.  

Nowhere was it mentioned that the vast majority of research found benefits from concealed carry.

Now take Murphy’s statement about 90 percent of Americans wanting stronger, expanded background checks.  Some polls don’t show anything even close to 80 to 90 percent support for background checks on private transfers of guns.  Some even show overall opposition to laws.  

Yet, even better than polls, three states have had ballot initiatives on expanded background checks and none have been close to 80 percent.  In 2014, an initiative in Washington state passed with 59 percent of the vote., Maine’s 2016 initiative was defeated by 8 percent, and Nevada’s passed this year with less than 50.5% of the vote.  And who knows if any of them would have passed if not for funding from Michael Bloomberg, who thoroughly outspent opponents of the initiatives by upwards of 50-to-1.

-- Throughout the 2016 presidential campaign, fact checkers continually defended Hillary Clinton from claims that she wanted the Supreme Court to reverse itself and allow complete gun bans.  But the reasoning was always strained. Fact checkers just argued that Clinton wasn’t trying to revise the Constitution. But the real concern was the impact that Clinton would have on the Supreme Court and its interpretation of the Second Amendment.

The bias here could include dozens of additional examples.  Facebook will also be relying on fact-checking by ABC News, Factcheck.org, and the Associated Press.  Yet all have shown similar left-wing bias (here, here, and here).

There is a way to deal with these supposedly dangerous “fake” news stories.  Simply nip them in the bud by explaining why they're wrong.  Unable to deal with the truth, however, liberals are again resorting to attempts at censorship.

John R. Lott, Jr. is a columnist for FoxNews.com. He is an economist and was formerly chief economist at the United States Sentencing Commission. Lott is also a leading expert on guns and op-eds on that issue are done in conjunction with the Crime Prevention Research Center. He is the author of nine books including "More Guns, Less Crime." His latest book is "The War on Guns: Arming Yourself Against Gun Control Lies (August 1, 2016). Follow him on Twitter@johnrlottjr.