Source: scientificamerican.com 11/4/24
What was once fair under the law may become unfair when science changes. The law must react to uphold due process
It’s been an astounding couple of weeks in the world where science and law intersect. Robert Roberson’s execution is delayed because everybody but the highest courts in Texas and the U.S. now realize that the medical theory on which he was convicted—shaken baby syndrome—originally rested on bad science. The life-without-parole sentences for Lyle and Erik Menendez, convicted of killing their parents, are also in question because researchers at the time did not understand the mental health effects of the abuse they suffered as children.
Whereas the law seeks to provide fair process in a timely fashion, science seeks to discover truth over time. This means that what was once fair may become unfair; the justice of yesteryear may be unjust today. Roberson and the Menendez brothers are the victims of that very divide.
In both cases, scientific understanding changed years ago. Shaken baby syndrome was called into question in the early 2010s, and, years before that, psychologists identified the relationship between the trauma of childhood abuse and violence. Yet all three men have struggled to reopen their cases. An essential principle of science is that it might change as research accumulates. That is a principle that the law has largely failed to come to grips with. This failure threatens the constitutional guarantee of due process.
The Roberson and Menendez cases are not abnormal. The annals of the law are replete with examples of what we once thought was scientific truth, upon which judges and juries decided both civil and criminal cases, where we later understood the science to be wrong. In 2004 the state of Texas executed Cameron Todd Willingham for the 1992 arson murders of his family. At the time of his execution, the forensic science that linked him to the fire had been categorically invalidated. In a 2015 press release, the FBI reported that in their ongoing review of non-DNA-based microscopic hair identification, 90 percent of cases had errors. Similarly, prosecutors’ use of a questionable theory known as comparative bullet-lead analysis was eventually abandoned after scientific reports debunked its statistical bases. Even today, courts continue to allow bite mark identification testimony, even though people who say they are bite mark experts can’t even agree on whether a bite mark is from a person—or a dog. And what we know about firearms identification and fingerprints are changing— there could be scores of convictions based on what is no longer true.
Society shifts quickly when science changes. Once upon a time, scientists told us that butter was bad for us, and margarine was better; then we learned how much worse margarine could be and started eating more butter again. With lives at stake, justice demands we shift quickly. Indeed, the Constitution’s guarantee of due process is so important that it appears in both the Fifth and 14th Amendments, and promises that “life, liberty, or property” will not be deprived without “due process.”
