In high school I took an advanced writing class, which required me to write a research paper of at least 10 double-spaced typewritten pages on a subject of my choosing (provided the instructor approved it). My paper was about the impact of nuclear power plants on aquatic life.

The instructor required every factual statement in the paper to have a footnote identifying its source. Not only was this requirement a pain (this was in the days before word processors; I had to write down every statement/source pair and save it on a three-by-five card), but my naive young mind wondered what the point was. If I’d gone to the trouble of uncovering various facts and putting them together in a coherent fashion for the reader, what difference did it make where I’d gotten them? (It never occurred to me that someone would just make stuff up.) But I did as I was told: The paper was diligently footnoted and had an extensive bibliography.

This training served me well in college, and especially in law school and in my career, where case citations and footnotes supporting legal arguments were always required. The older I got, the more I appreciated footnotes. They allowed a reader to dig down and see not only if the writer had characterized the source correctly, but also whether the source itself was credible. They were a defense against poor thinking, laziness, or outright deception.

In today’s world of “alternative” facts, propaganda, memes, and on-line out-and-out lies, we need a defender of facts. Misinformation spread on social media is polluting our politics and dividing us. People believe false things because their “friends” do. They may not know it is false. But once they repost a falsehood, they are invested in it, and will defend the truth of the falsehood mindlessly.

Footnotes to the rescue! Facebook and other social media outlets should be required to retool their platforms so that no statement about an issue in the public sphere could be posted without a footnote citing a reputable source as support for the statement. Multiple statements would require multiple footnotes. Posters who repeatedly violated this footnote requirement would be kicked off the platform.

I know that fights will erupt about what is or is not a “reputable” source. (Unfortunately, just like Justice Stewart’s comment about obscenity, the line isn’t always clear, but “I know it when I see it." But that can be worked out among experts on the left, right, and center acting in good faith. I know, too, that the line between fact and opinion isn’t always bright. The point of the footnote requirement isn’t to unreasonably circumscribe the sources available to posters, or to keep them from expressing opinions. The point is to make a poster stop and think “is this true? how do I know this is true?” before posting or reposting, rather than blindly assuming that it is its truth because it came from a friend.

Facebook and other social media platforms will object to the imposition of the footnote requirement and balk at having to police it. However, AI could take care of a lot of it, and if Facebook has to hire additional employees to meet the requirements, well boo-hoo, they’re making billions of dollars and are largely unregulated. Facebook might also object on First Amendment grounds, but the requirement doesn’t affect Facebook’s speech, and no one has an absolute First Amendment right to post lies on a social media site.

A simple solution to the spread of propaganda; the humble footnote could save our democracy.