In 2018, my colleague James Phillips and I published a post on the Harvard Law Review Blog. We offered some tentative findings about the linguistic claims made by the majority and dissent in D.C. v. Heller. Since then, James was hired as an associate professor at the Chapman University Fowler School of Law. As James transitions to academia, we plan to submit for publication a much more detailed version of our research. In the interim, we published an essay in The Atlantic that previews our work. We show that both Justice Scalia and Justice Stevens erred.

Here is a segment that focuses on the phrase "keep arms"

Next, we turn to Justice Stevens's dissent. He wrote that the Second Amendment protected a right to have and use firearms only in the context of serving in a state militia. Stevens appears to have determined—though his exact conclusion is somewhat unclear—that the phrase keep and bear arms was a unitary term of art. Such single linguistic units, called binomials or multinomials, are common in legal writing. Think of cease and desist or lock, stock, and barrel. As a result, Stevens concluded, there was no need to consider whether keep arms had a different meaning from bear arms. Therefore, he had no reason to determine whether keep arms, by itself, could refer to an individual right. Was Stevens's linguistic intuition correct? No. The phrase keep and bear arms was a novel term. It does not appear anywhere in COEME—more than 1 billion words of British English stretching across three centuries. And prior to 1789, when the Second Amendment was introduced, the phrase was used only twice in COFEA: First in the 1780 Massachusetts Declaration of Rights, and then in a proposal for a constitutional amendment by the Virginia Ratifying Convention. In short, keep and bear arms was not a term of art with a fixed meaning. Indeed, the meaning of this phrase was quite unsettled then, as it had barely been used in other governmental documents. Ultimately, a careful study of the Second Amendment would have to treat keep arms and bear arms as two separate linguistic units, and thus two separate rights. We performed another search in COFEA, about the meaning of keep arms, looking for documents in which keep and arms (and their variants) appear within six words of each other. The results here were somewhat inconclusive. In about 40 percent of the hits, a person would keep arms for a collective, military purpose; these documents support Justice Stevens's reading. And roughly 30 percent of the hits reference a person who keeps arms for individual uses; these documents support Justice Scalia's analysis. The remainder of the hits did not support either reading. We could not find a dominant usage for what keep arms meant at the founding. Thus, even if Scalia was wrong about the most common meaning of bear arms, he may still have been right about keep arms. Based on our findings, an average citizen of the founding era would likely have understood the phrase keep arms to refer to possessing arms for both military and personal uses.

James and I were also cited in a recent New York Times Magazine profile on originalism.

For originalists, the new tool is "a paradigm-shifting technology," two members of the Federalist Society, the law professor Josh Blackman and the Stanford law fellow James C. Phillips, wrote in The Harvard Law Review's blog in August 2018. It also means that cherry-picking the historical record to establish a dubious "original" meaning would be harder to conceal. "We can do empirics," says Alison LaCroix, a historian and law professor at the University of Chicago. "There's a data set." Blackman and Phillips conducted a review of the database and found that the dominant use of "bear arms" at the time of the country's founding related to the militia. (Even so, they didn't conclude that Scalia got Heller wrong.) LaCroix and three linguists submitted a brief to the court last fall, in the New York case, with studies they had each done. One found that references in the database "to hunting or personal self-defense" for the phrase "bear arms" were "not just rare, they are almost nonexistent." The phrase "keep arms," the brief stated, was also used "almost exclusively in a military context." The findings confirm what Rakove and his fellow historians showed about the era's political history. But this time, the analysis played by the rules of the game as Scalia defined them, by looking narrowly at the original public meaning of the text. "I don't care how big a fan of Justice Scalia you are," Phillips told me. "At some point, you run up against the data."

(We disagree with some of the quotes from the other professors.)

Our goal here was not to criticize Justice Scalia. Linguistic analysis formed only a small part of Scalia's originalist opus. And the bulk of that historical analysis, based on the history of the common-law right to own a firearm, is undisturbed by our new findings. But originalists should still be able to assess, critically where Justice Scalia faltered. And Heller critics should likewise acknowledge where Justice Stevens faltered.

Finally, we offer this observation in our essay:

Corpus linguistics, like any tool, is more useful in some cases than in others. The Second Amendment in particular poses distinct problems for data searches, because it has multiple clauses layered in a complicated grammatical structure.

Our ultimate conclusion highlights some of the limits of corpus linguistics, at least with respect to the Second Amendment.