With that in mind, in mid-2018 we searched large collections of language from around the time of the founding, and published our tentative findings on the Harvard Law Review’s blog. We used two databases: the Corpus of Founding Era American English (COFEA), which contains about 140 million words of text from various American documents published from 1760 to 1799, and the Corpus of Early Modern English (COEME), which covers British English from 1475 to 1800 and includes more than 1 billion words of text. We have now expanded that initial research to consider how other aspects of the Second Amendment were understood at the time of the framing. Our findings show that both Scalia and Stevens appear to have been wrong with respect to at least one of their linguistic claims in the Heller decision.

John Paul Stevens: The Supreme Court’s worst decision of my tenure

In 2008, technology was in a very different place. The iPhone was less than a year old. The format war between Blu-ray and HD DVD drew to a close. And Twitter celebrated its second anniversary. At the time, the justices and their law clerks had fairly rudimentary tools to search how language had been used 200 years earlier. Based on the limited data set Scalia considered, we can’t say his linguistic claim about bear arms against was unsupported then. But this specific conclusion does not stand the test of time.

Scalia concluded that the phrase bear arms “unequivocally” carried a military meaning “only when followed by the preposition ‘against.’” The Second Amendment does not use the word against. Therefore, Scalia reasoned, the phrase bear arms, by itself, referred to an individual right. To test this claim, we combed through COFEA for a specific pattern, locating documents in which bear and arms (and their variants) appear within six words of each other. Doing so, we were able to find documents with grammatical constructions such as the arms were borne. In roughly 90 percent of our data set, the phrase bear arms had a militia-related meaning, which strongly implies that bear arms was generally used to refer to collective military activity, not individual use. (Whether these results show that the Second Amendment language precludes an individual right is a more complicated question.)

Further, we found that bear arms often took on a military meaning without being followed by against. Thus, the word against was sufficient, but not necessary, to give the phrase bear arms a militia-related meaning. Scalia was wrong on this particular claim.

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.