Everyone from scholars to Supreme Court justices has debated footnotes vs. endnotes, and online writing has incorporated hyperlinks as a hassle-free way of citing sources, albeit not one without flaws.

But the format is not the point: It’s the principle and the function behind the reference tool that’s so essential. It allows us to weigh evidence against assertion. A footnote reveals the load-bearing structure of a piece of writing, whether it is scientific research, historical analysis or a legal finding...

The footnote, as historian Anthony Grafton observed, allows readers “purchase, leverage, an Archimedean point from which to shift and crack the … certainties of the text they supposedly support.”

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The footnote was developed in an era of information scarcity, but we are now in an era of information profusion, and it’s never been so necessary. We all ought to be acknowledging the sources on which our work relies, and demanding it from others. Where footnoting isn’t practical, there are other ways to accomplish citation. We ought to know — in fact, we need to know — the foundation for claims.

Accurate, full and contextualized information is the most important weapon wielded on behalf of accountable and transparent government. That is why despotic regimes want to control and restrict it. It is why we have the First Amendment, guaranteeing freedom of the press. It is the heart of the Freedom of Information Act. Information itself is democracy’s shield and sword, and the footnote every American’s birthright.