Chief Justice John G. Roberts Jr. studied history in college and wanted to become a historian. A taxi ride changed his mind.

“I was being driven back to school and started talking with the cabdriver, and he said, ‘What do you do?’” the chief justice recalled at Georgetown’s law school in May. “I said, ‘I’m a history major at Harvard.’”

The cabdriver responded that he, too, had been a history major at Harvard.

The exchange was a turning point. “I decided — nothing against cabdrivers — that law school seemed like a reasonable alternative,” Chief Justice Roberts said.

The chief justice might have tried to leave history behind, but it has caught up with him. As the Supreme Court’s decisions increasingly turn on their understanding of the distant past, the number of supporting briefs from historians has exploded and their influence has grown.

Indeed, Justice Sonia Sotomayor said in 2023 that such filings, which lawyers call amicus briefs, are “probably today the most important kinds of briefing,” considering “the composition of the court and the direction it’s been moving in and its jurisprudence.” She was referring to originalism, which seeks to determine the meaning of the Constitution when it was adopted.

Judge Jeffrey S. Sutton, a prominent federal appeals court judge, was already marveling at the beginnings of the phenomenon in a 2009 law review article, noting that “honest-to-goodness historians, as opposed to lawyer historians,” had filed supporting briefs in major Supreme Court cases on the Second Amendment and efforts to combat terrorism.