Facebook is right to continue its policy of not moderating political advertising. It is wisely leaving the act of fact-checking such ads to its customers.

The online media giant has provided mixed signals, however, regarding the principle that drove its decision to stick with its generally hands-off approach to political campaigns’ communications.

“We don’t fact-check political ads,” Facebook founder Mark Zuckerberg said in an October speech at Georgetown University. “We don’t do this to help politicians, but because we think people should be able to see for themselves what politicians are saying.”

In the same speech Mr. Zuckerberg also sensibly addressed the accusation that in failing to pick and choose between ads, Facebook was open to permitting false advertising.

“Even when there is a common set of facts, different media outlets tell very different stories emphasizing different angles,” he said. “... And while I worry about an erosion of truth, I don’t think most people want to live in a world where you can only post things that tech companies judge to be 100% true.”

At odds with the First Amendment-friendly theme of Mr. Zuckerberg’s speech was a recent blog post by the official who oversees the company’s advertising integrity division.

“In the absence of regulation, Facebook and other companies are left to design their own policies,” Rob Leathern, Facebook’s director of product management, said in the post.

That seems like an invitation to just the sort of regulation Mr. Zuckerberg’s stance demands be resisted.

Just as no American would want Mr. Zuckerberg refereeing a dinnertime political discussion, the government also has no place at that table.

It is through the free exchange of ideas that the best rise to the top. The Founders adopted the First Amendment to deny Congress the power to regulate speech, political or otherwise. It’s a principle worthy of respect on all fronts.

First Published: January 24, 2020, 11:15 a.m.