The Social Media Fact-Check Farce

In recent years liberals have successfully lobbied social-media companies to police conservative content more and more aggressively. But there’s little evidence that this political interference has reduced the prevalence of misinformation online—and a new study shows how it could make the problem worse.

In the study—by Dino Christenson of Boston University and Sarah Kreps and Douglas Kriner of Cornell—volunteers were shown a May 26 tweet by President Trump attacking mail-in voting and claiming that “Mail boxes will be robbed, ballots will be forged & even illegally printed out & fraudulently...