The law must respond when science evolves

By David L. Faigman & Jeff Kukucka

These last few weeks have been astonishing in the world, at the intersection of science and law. The execution of Robert Roberson is late because everyone except the highest courts in Texas and the United States now realizes that the medical theory on which he was convicted – shaken baby syndrome – was originally based on bad data scientists. The life sentences without parole handed down to Lyle and Erik Menendez, convicted of murdering their parents, are also in question because researchers at the time did not understand the mental health effects of the abuse they suffered in their childhood.

While the law seeks to ensure a fair process in a timely manner, science seeks to uncover the truth over time. This means that what was once just can become unjust; the justice of yesteryear can be unjust today. Roberson and the Menendez brothers are victims of this same division.

In both cases, scientific understanding changed years ago. Shaken baby syndrome was questioned In the beginning of the 2010sand years before, psychologists had identified the relationship between the trauma of childhood abuse and violence. However, the three men had difficulty reopening their case. An essential principle of science is that it can evolve as research accumulates. This is a principle that the law has largely failed to address. This failure threatens the constitutional guarantee of due process.

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The Roberson and Menendez cases are not anomalous. The annals of law are replete with examples of what we once thought was scientific truth, on the basis of which judges and juries ruled in civil and criminal cases, as we later understood science to be false. In 2004, the State of Texas executed Cameron Todd Willingham for the arsons of his family in 1992. At the time of his execution, the forensic knowledge linking him to the fire had been categorically invalid. In a 2015 press release, the FBI reported that in its ongoing review of microscopic identification of hair without DNA, 90 percent cases contained errors. Similarly, prosecutors’ use of a dubious theory known as lead comparative analysis was ultimately abandoned after scientists debunked reports its statistical bases. Even today, courts continue to allow bite mark identification testimony, even though people who call themselves bite mark experts can’t even agree on whether a bite mark comes from a person or a dog. And what we know about gun identification and fingerprints is evolving: There could be dozens of beliefs based on what is no longer true.

Society changes quickly when science evolves. Once upon a time, scientists told us that butter was bad for us and that margarine was better; then we learned how much worse margarine could be and started eating more butter again. With lives at stake, justice demands that we act quickly. Indeed, the constitutional guarantee of due process is so important that it appears in the Fifth and Fourteenth Amendments, and promises that “life, liberty, or property” shall not be deprived of “due process of law.”

The law, which is never an informed consumer of science, must become one. When scientific evidence is part of a criminal prosecution, the U.S. justice system must take two critical steps to ensure due process.

Judges are supposed to be “guardians” against bad science being introduced into their courtrooms; this is how the Supreme Court interpreted a rule of evidence in Daubert v. Merrell Dow Pharmaceuticals in 1993. They must do more to fulfill this obligation. In fact, if they fail to meet this responsibility, defendants will be wrongly convicted and future courts will be called upon to correct these miscarriages of justice.

For example, the scientific literature supporting the use of pre-1995 arson investigations or the identification of hair without DNA or bite markswas – and still is – clearly insufficient to be admitted in court, let alone to support a conviction on its own. In 2009, the National Academies of Sciences published a scathing report on the state of forensic science. In 2016, the President’s Council of Science and Technology Advisors reviewed scientific research on several areas of forensic pattern matching evidence – including DNA, latent fingerprints, bite marks, firearms, hair and shoes – scientific support only for DNA profiling and to give fingerprints a barely satisfactory grade.

Second, the law must provide mechanisms for post-conviction relief based on a new understanding of science, which of course includes when the courts got it wrong the first time. They may do so, for example, through judicial interpretation of due process clauses or legislative action. Texas has just such a law on its books, although enforcement has so far been anemic. Under Texas lawa habeas corpus petition may be considered if “relevant (and admissible) scientific evidence is currently available and was not available at the time of the convicted person’s trial because it was not verifiable through the exercise of ‘due diligence… before the trial date. or during the trial of the convicted person. In other words, a convicted person, like Roberson, can ask the court to reconsider their case because the scientific evidence has changed.

California has a similar situation lawwhich makes it possible to challenge the “false evidence” presented at trial. False evidence is defined to include “expert opinions that have been repudiated by the expert who originally provided the opinion in a hearing or trial or that have been undermined by scientific research or advances subsequent technological developments. Other states are following suit.

But these efforts are at best illusory, and at worst unacceptable, if the courts do not implement them. Roberson has been on death row for twenty years and the Menendez brothers were convicted more than 28 years ago. The state of Texas rejected Roberson’s attempts to appeal, despite what we now know about shaken baby syndrome. The time it took to reconsider the Menendez brothers’ conviction far exceeds the time it will take for the science on abuse, trauma, and violence to change.

American law traditionally provides mechanisms to ensure that everyone has the right to a fair chance in court. Fairness requires the opportunity to have their case judged in light of the best scientific data currently available. And when the stakes are particularly high, as is the case in the cases of Roberson and the Menendez brothers, those with criminal convictions should have the permanent right to reopen their cases when our understanding of the science behind their threat has exchange. Such an outcome would allow fairness and truth to come together to ensure justice is done.

This is an opinion and analysis article, and the opinions expressed by the author(s) are not necessarily those of Scientific American.