Saul Cornell’s corner of academia has historically been sleepy. So few scholars share his specialty that the Fordham University professor jokes that he and his colleagues could hold a national convention “in an English phone booth.”

But in the months since a landmark Supreme Court decision upended the standards for determining the constitutionality of gun laws, Dr. Cornell has been booked solid. An authority on the history and laws around American weapons, he has served as an expert witness in at least 15 federal cases on gun control laws, which is roughly 14 requests more than he used to get in a busy year.

Gun historians across the country are in demand like never before as lawyers must now comb through statutes drafted in the Colonial era and the early years of the Republic to litigate modern firearms restrictions. From experts on military gun stamping to scholars of American homicide through the ages, they have been called — many for the first time — to parse the nation’s gun culture in court.

Cases now explore weapons bans in early saloons, novelty air rifles on the Lewis and Clark expedition, concealed carry restrictions on bowie knives and 18th-century daggers known as “Arkansas toothpicks,” and a string-operated “trap gun” that may or may not be comparable to an AR-15 semiautomatic rifle.

“This is what the courts have unleashed upon us,” said Darrell A. H. Miller, a Duke University law professor and faculty co-director at the Duke Center for Firearms Law. “Suddenly everyone is looking for early Republic scholars to tell them what the culture and norms around firearms law were in the 18th century.”

In a 6-3 decision last June, the Supreme Court dramatically shifted the standard for firearm restrictions. Writing for the majority in New York State Rifle & Pistol Association v. Bruen, Justice Clarence Thomas found that gun laws should be judged not by the longstanding practice of balancing gun rights against the public interest, but according to the Second Amendment’s text and the “historical tradition” of gun regulation.

The constitutionality of gun constraints, he suggested, would hinge on whether the government could show a “historical analogue” in the law, either in 1791 when Americans ratified the right to bear arms, or around 1868, when the Fourteenth Amendment extended protections against federal infringements on gun rights to the states.

That originalist view has been celebrated by gun rights advocates for strengthening a constitutional right and presenting a wide-open opportunity to erase gun control laws. Many others, seeking stricter controls against a crushing epidemic of gun violence, say that it is dangerous and absurd to base modern public safety on the 1700s and 1800s when a gun can be built with a 3-D printer and plans shared on the internet.