Can journalists on the right honestly fact-check journalists on the left? That question erupted this week in a fight over Brett Kavanaugh’s Supreme Court confirmation hearings. The fight, as promised, has exposed media bias. But in this case, the bias is on the left.

The dispute centers on an article published on Sunday by ThinkProgress. The piece, written by Ian Millhiser, argues that Kavanaugh’s answers at his confirmation hearing last week, when combined with a speech Kavanaugh delivered last year, imply that he would overturn Roe v. Wade. It’s a smart and well-written piece. But the headline goes further. It claims that Kavanaugh “said he would kill Roe v. Wade.”

The Weekly Standard, in its “fact check,” said the headline wasn’t true. The author, Holmes Lybrand, wrote: “While ThinkProgress engages in an argument to suggest how Kavanaugh might vote in a Roe v. Wade redo, the article does not provide evidence that ‘Kavanaugh said he would kill Roe v. Wade.’ ” Lybrand delivered the same verdict against MoveOn.org for claiming that Kavanaugh “stated he’d overturn” Roe. He reported that “TWS Fact Check could not find” such a statement from Kavanaugh.

Based on the Standard’s fact check, Facebook declared the ThinkProgress article “false.” This led to a warning label and an editorial demotion of the article on Facebook. Whether Facebook should issue such labels and demotions at all is worth debating. But ThinkProgress and its allies haven’t focused on that question. Their complaint is more specific: They want the Standard to be removed from Facebook’s list of approved fact-checking organizations, on the grounds that the magazine is biased.

Millhiser, in a follow-up article, dismisses the Standard’s fact-checking as “ideological” and accuses the magazine of “placing right-wing ideology before accurate reporting.” He warns: “If Facebook continues its partnership with The Weekly Standard, the consequences could be quite severe for left-leaning outlets generally—or potentially for any other outlet which publishes a news article that The Weekly Standard disagrees with.” Judd Legum, the founding editor of ThinkProgress, says Millhiser’s article was rated false only because “a hack at a right-wing magazine has decided he doesn’t like” it.

Other journalists have joined in this accusation. “@weeklystandard naturally wanted to censor it, because @weeklystandard is unscrupulous,” says one. “Facebook has given the Weekly Standard the power to drive liberal news outlets into the ground,” says another. “This is what happens,” says a third, “when you let non-reality-based organizations into the fact-checking community to achieve ‘balance.’ ” My Slate colleague Mark Joseph Stern presents the best version of the argument. “By deferring to the Weekly Standard’s judgment, Facebook is picking sides in an ideological debate,” he writes. “Facebook should not let conservative editors police liberal outlets’ analysis under the guise of fact-checking.”

These writers have done a lot of good work. But in this case, they’re mistaken. This is a matter of fact, not ideology. On Facebook, headlines are far more visible and widely read than articles are. The headline on the ThinkProgress article was false. Kavanaugh didn’t say he would kill Roe. And the Standard was right to point this out.

The Standard has offered to withdraw the “false” rating if ThinkProgress changes its headline. But as of Wednesday, ThinkProgress hadn’t budged. Millhiser insists the headline is true. According to Merriam-Webster, he argues, “the verb ‘say’ or ‘said’ can mean to ‘indicate,’ ‘show,’ or ‘communicate’ an idea.” He maintains that Kavanaugh “indicated, showed, or communicated his intention to overrule Roe” by doing two things. First, a year ago, Kavanaugh said that a 1997 Supreme Court opinion, Washington v. Glucksberg, was “not consistent” with Roe and Planned Parenthood v. Casey, the 1992 opinion that reaffirmed Roe. Second, during last week’s hearings, Kavanaugh said “all roads lead to the Glucksberg test” as the Supreme Court’s rule for defining rights not enumerated in the Constitution.

This is an interesting argument. But it doesn’t show that Kavanaugh “said” he would kill Roe. Let’s start with the dictionary entry Millhiser cited. It defines “say” as “state,” “declare,” “utter,” or “recite.” The only cases in which the definition refers to softer interpretations—“indicate,” “show,” or “communicate”—are when the act is nonverbal. The dictionary gives two examples: “the clock says five minutes after twelve,” and “a glance that said all that was necessary.” Kavanaugh is a person, not a clock. He spoke in words, not glances. To prove he said something, you have to show he said it.

ThinkProgress and its allies have demonstrated why we need conservative journalists to help check facts.

Second, at his hearings, Kavanaugh was asked several times what he thought of Roe. He refused to address the substance of the case. It’s misleading to report that he “said he would kill Roe” when in fact he declined explicit invitations to say he would kill Roe.

Third, Kavanaugh’s 2017 remark that Roe, Casey, and Glucksberg were “not consistent” in their “approach” wasn’t absolute. He noted that although a majority of the court voted in Glucksberg not to assert a specific constitutional right to bodily autonomy (in that case, the issue was assisted suicide), a majority hadn’t voted that way five years earlier in Casey. (In fact, the court explicitly reasoned that Glucksberg and Casey were compatible.) Justice Anthony Kennedy, for whom Kavanaugh clerked—and whose seat Kavanaugh would fill—voted with the conservatives in Glucksberg but also voted in Casey to reaffirm Roe. So you can’t declare, as Millhiser does, that it’s a matter of simple logic to conclude that Kavanaugh “said he would kill Roe.”

Fourth, Kavanaugh repeatedly emphasized at his hearings that Roe could no longer be overturned on its merits alone. He said the court would now have to overcome the additional weight of Casey, which reaffirmed Roe based on stare decisis, a doctrine of deference to precedents. (Kavanaugh made the same point in his 2017 speech: that stare decisis might be why the court reaffirmed Roe, even as it voted the other way in Glucksberg.) In short, Kavanaugh explained why you can’t infer that a judge who believes Roe was wrongly decided would overturn Roe today.

So the Standard’s fact check is correct. By itself, that’s a small point. But ThinkProgress and its allies have made the dispute into something much bigger. By attacking the fact check as biased on the grounds that a conservative magazine published it, they’ve proved the opposite of what they intended. They’ve confirmed that the press is full of left-leaning journalists who sometimes can’t see or acknowledge congenial falsehoods, and they’ve demonstrated how these journalists unite, when challenged, in a tribal chorus to accuse conservatives of trying to “censor” them. In sum, they’ve demonstrated why we need conservative journalists to help check facts.

ThinkProgress does excellent fact-checking of lies on the right. In these cases, it applies the sensible rule that if a person didn’t say something, you can’t accuse him of saying it. Over the years, ThinkProgress has invoked this rule in defense of Barack Obama, Joe Biden, James Comey, and James Clapper, among others. But when the same rule is applied to ThinkProgress, it accuses the fact-checker of ideological hackery. And it calls for the Standard to be removed from Facebook’s panel of approved fact-checking organizations, even though other organizations on the panel, in assessing the Kavanaugh hearings, have applied the same rule.

Watching my colleagues rationalize the false headline, accuse the Standard of imposing ideological censorship under the guise of fact-checking, and castigate Facebook for allowing “non-reality-based organizations into the fact-checking community” is humbling. It’s a reminder that most of us, including me, are good at seeing other people’s biases but lousy at seeing our own. PolitiFact, in its initial report on the Kavanaugh hearings, said the nominee “raised a few eyebrows” when he “called birth control pills abortion-inducing drugs.” Days later, PolitiFact conceded that it had “repeated uncritically a Democratic talking point” and that Kavanaugh had actually been quoting a party in the case. I don’t see any of my colleagues on the left calling for PolitiFact to be removed from Facebook’s panel.

If progressives insist that anyone who challenges them is “non-reality-based”—and that the Weekly Standard’s name on a fact check “tells you all you need to know about how messed up Facebook’s notion of ‘fact-checking’ is”—they’ll seal themselves off in a bubble of mutual affirmation. David Roberts, a Vox blogger, made the key point in a tweet about Millhiser’s article. “A society can’t survive long without shared epistemic authorities and standards,” Roberts wrote. He was echoing Millhiser’s attack on the Standard. But in this case, it’s the Standard that is upholding shared epistemic rules. Said means said.

The Standard often gets things wrong. So does everybody else. We’re all fallible, but we can fact-check one another. In any industry where one group predominates—whites in the corporate elite, men in the entertainment business, liberals in the media—we need scrutiny from people who don’t share the prevailing biases. That’s why the Weekly Standard is on Facebook’s fact-checking panel. And it is doing its job.