WASHINGTON — The Supreme Court on Thursday ruled against a convicted drug mule from California who objected to evidence admitted at her trial that suggested she would have been aware of thousands of dollars’ worth of methamphetamine found in her car.
The 6-3 ruling means Delilah Guadalupe Diaz's conviction is upheld.
Diaz has maintained that she was a "blind" mule, a term for someone who transports drugs unwittingly.
Diaz, a U.S. citizen living in California, was stopped by a Border Patrol agent in August 2020 after having crossed into the U.S. from Mexico at the San Ysidro port of entry.
A search revealed 55 pounds of methamphetamine with a retail value of $368,550.
Diaz, who was sentenced to seven years in prison, said her boyfriend had lent her the car when she was returning to the U.S. from a trip to Mexico.
The case focused on a rule of evidence that was amended after John Hinckley Jr. was found not guilty based on his insanity defense for the attempted assassination of President Ronald Reagan in 1981. Congress changed the rule in an effort to exclude testimony by expert witnesses about defendants’ mental state.
The rule says that “an expert witness must not state an opinion about whether the defendant did or did not have a mental state or condition that constitutes an element of the crime charged or of a defense.”
At Diaz’s trial, a Department of Homeland Security agent testified that drug cartels do not normally allow so-called blind mules who are not aware of their cargo to transport large quantities of drugs.
Diaz’s lawyer tried and failed to have the testimony excluded, saying it was the “functional equivalent” of telling the jury that she knew about the drugs.
In Thursday's ruling, Justice Clarence Thomas said Flood "did not state an opinion about whether petitioner herself had a particular mental state," as he was merely speaking to what usually happens in similar situations. As a result, his testimony did not violate the evidence rule.
The jury, he added, was "well aware" of the existence of blind drug mules and that Diaz could have been one but ultimately concluded that the evidence "pointed to a different conclusion: that Diaz knowingly transported the drugs."
Conservative Justice Neil Gorsuch wrote a dissenting opinion joined by two of the court's liberals, Sonia Sotomayor and Elena Kagan.
He heavily criticized the ruling, saying it gives prosecutors "a powerful new tool" by allowing them to call witnesses who can hint at defendants' guilt as part of their expert testimony.
"Prosecutors can now put an expert on the stand — someone who apparently has the convenient ability to read minds — and let him hold forth on what 'most' people like the defendant think when they commit a legally proscribed act," he wrote.
During arguments in the case in March, a lawyer representing the Justice Department told the justices that prosecutors do not need to introduce the kind of evidence submitted in Diaz's case to secure convictions.
