Elizabeth Warren’s presidential campaign has a new Facebook ad claiming Mark Zuckerberg, the CEO of Facebook, has endorsed Donald Trump for re‐​election. That claim is false, and Warren admits as much in the ad. Warren is not trying to mislead people about Zuckerberg. She is trying to control what can be said on Facebook. That is much more dangerous than any lie appearing in a campaign ad.

Recently the Trump campaign ran an ad on Facebook saying former vice president Joe Biden had sought to fire a Ukrainian prosecutor investigating a company whose board included Biden’s son. Many on the left like Warren think this claim is a bald‐​faced lie. Trump’s supporters probably think it’s obvious something is rotten in the state of Ukraine. Many others, not all fans of the President, find the charges plausible. The Hill newspaper gingerly calls the Biden claims “unsubstantiated allegations.”

Facebook does refer some content to external fact‐​checkers. For example, this morning my Facebook feed had a story that House Speaker Pelosi was diverting Social Security funds to pay for the impeachment inquiry of President Trump. The post was followed by a link to a fact check organization that reported the story was false. Notice that Facebook did not suppress the story. In classic First Amendment style, they provided “more speech” and let the users of the platform make up their own minds.

Facebook has also recently decided to exempt speech from politicians from fact‐​checking for good reason. What politicians say (including falsehoods) provokes criticisms and “more speech.” Trump’s charges about Biden have been widely attacked and defended for some time. The Trump Facebook ad itself and the company’s policies have been widely reported and debated. Those who wish to make up their mind have much to read, hear, and ponder.

Why is that exemption good? Consider the alternative. Nick Clegg, a Facebook Vice President, has rightly noted, “Would it be acceptable to society at large to have a private company in effect become a self‐​appointed referee for everything that politicians say?…In open democracies, voters rightly believe that, as a general rule, they should be able to judge what politicians say themselves.” Facebook thus gives priority to freedom of speech on its platform.

But the problem goes deeper than simply denying voters the right of judgment. Elizabeth Warren is demanding that Facebook suppress speech she finds false. But that is not a desirable standard in our politically polarized times. Strident partisans believe everything the other side says is a lie. If Facebook were to adopt the Warren standard for acceptable speech, much valuable speech would be suppressed. And some of it would come from Elizabeth Warren. As a private company, Facebook does not have to obey the First Amendment. But following Warren here would greatly diminish democracy.

Ms. Warren is appealing to Democratic primary voters for whom Facebook is “too big” and the President is an inveterate liar. But we should consider the bigger picture. Ms. Warren may become president, an office with much discretionary power. Beyond her antitrust crusade, President Warren and her allies in Congress would have many ways to harm Facebook. Her current demands to control speech and advertising on Facebook pose a real risk to that company.

But all this involves more than a company’s fate. No one has First Amendment rights against Facebook. If Warren wins this fight, elected officials in the future can suppress the Facebook speech of their critics with impunity. Do Elizabeth Warren’s supporters really want to live in that world if President Trump is re‐​elected? Do any of us want to live in that world?

Many people complain about Facebook’s size and market dominance. In this case, the company’s importance enables Facebook to push back against Warren’s implicit threats. Politicians do indeed lie and wish to censor speech. Zuckerberg is unwilling to help them censor and trusts Americans to evaluate the lies. Make no mistake. If the angels favor free speech – and I think they do – Mark Zuckerberg is on their side.