U.S. Supreme Court Justice Stephen Breyer, who is expected to announce his retirement tomorrow, has made a notable impact on the use of science in the courtroom during his 27 years on the nation’s highest court. In particular, in opinions and other writings, Breyer helped clarify how federal judges should handle expert testimony on scientific or technical issues.
“[T]he law itself increasingly requires access to sound science,” Breyer wrote in a 1998 essay for Science, in which he argued that judges increasingly needed education about technical issues. In particular, he noted that Supreme Court decisions—including one he would later write—empowered federal judges to decide what kinds of expert testimony to allow into the courtroom. “[T]he law imposes on trial judges the duty, with respect to scientific evidence, to become evidentiary gatekeepers,” he wrote, and “determine whether purported scientific evidence is ‘reliable.’”
A few years later, in Issues in Science and Technology, Breyer wrote that legal proceedings were not necessarily a “search for scientific precision. We cannot hope to investigate all the subtleties that characterize good scientific work. But the law must seek decisions that fall within the boundaries of scientifically sound knowledge.”
Among those who follow science in the courts, Breyer is especially known for the 1999 decision he authored in Kumho Tire Co. v. Carmichael. It built on two previous opinions, in Daubert v. Merrell Dow Pharmaceuticals and General Electric v. Joiner, that set standards for admitting expert witnesses. In Kumho, which focused on the use of expert testimony in a lawsuit involving a death resulting from the failure of a car tire, the court ruled that a judge’s gatekeeping authority applied not just to testimony from scientists, but also to testimony from engineers and other technical specialists. “[I]t would prove difficult, if not impossible, for judges to administer evidentiary rules under which a gatekeeping obligation depended upon a distinction between ‘scientific’ knowledge and ‘technical’ or ‘other specialized’ knowledge,” Breyer wrote in his opinion for the court. “There is no clear line that divides the one from the others.”
In Kumho, Breyer “pithily boiled down the gatekeeping that courts do before allowing expert witnesses to testify to a jury,” says attorney Patrick Malone of Patrick Malone & Associates, who is a former member of the U.S. National Academy of Sciences’ Committee on Science, Technology, and Law. “Nobody has said it better before or since.”
At 83, Breyer is the court’s oldest justice. Nominated by former President Bill Clinton, Breyer won Senate confirmation in 1994, in hearings led by then-Senator Joe Biden. Breyer has been the court’s leading expert on administrative law, which can be key in cases that focus on whether federal agencies have correctly considered all kinds of information—including technical information—in making decisions. In 2019, for example, Breyer was part of a five-to-four majority that ruled then-President Donald Trump’s administration had not followed proper procedures in making its controversial decision to add a question about citizenship to the 2020 census. “[T]he decision was ill considered in a number of critically important respects,” Breyer wrote in a concurring opinion, because the decision did not adequately consider issues “such as the high likelihood of an undercount, the low likelihood that a question would yield more accurate citizenship data, and the apparent lack of any need for more accurate citizenship data to begin with.”
As president, Biden will have an opportunity to name Breyer’s replacement and has said he would like to appoint a Black woman to the court. Breyer is expected to formally retire in June, at the end of the court’s current term.