On June 21, 2024, the United States Supreme Court reaffirmed the scope of the Confrontation Clause of the Sixth Amendment, particularly how it applies to forensic evidence presented to a jury by an expert relying on the work and findings of a different, non-testifying analyst.

Background and Case Summary
Smith v. Arizona, 144 S. Ct. 478 (2023), addressed whether a substitute lab analyst can opine based on a non-testifying analyst’s findings without violating a defendant’s confrontation rights. The case arose from a drug possession charge where the original, non-testifying, analyst’s findings were relied on by another analyst to reach an opinion, which was presented to the jury.  The defendant was denied the opportunity to confront the non-testifying analyst.

Court’s Decision
The Supreme Court ruled that when a testifying expert relays a non-testifying analyst’s findings, and the accuracy or truthfulness of the non-testifying analyst underpin the testifying expert’s opinion testimony, and those findings are essential to the case, they are effectively testifying on behalf of the absent analyst and thus violate the Confrontation Clause.

Writing for the majority, Justice Kagan summarized the Court’s view:

“Here, [the non-testifying analyst’s] statements came in for their truth, and no less because they were admitted to show the basis of [the testifying analyst’s] expert opinions. All of [the testifying expert’s] opinions were predicated on the truth of [the non-testifying analysts] factual statements. And the jury could credit those opinions because it too accepted the truth of what [the non-testifying analysts] reported about her lab work. So, the State’s basis evidence—more precisely, the truth of the statements on which its expert relied—propped up the whole case; yet the maker of the statements was not in the courtroom, and [the defendant] could not ask her any questions.

Implications for Criminal Defense
From a defense perspective, this ruling fortifies defendants’ constitutional rights. It ensures that defendants can challenge expert opinion evidence by cross-examining those who developed its factual basis. The case may have broader implications:

  1. When opinion testimony is presented to a jury, defense counsel should object to its admissibility unless the prosecution presents testimony from witnesses who gathered or produced the underlying facts.
  2. Without such testimony, the expert opinion may violate the Confrontation Clause.

This decision underscores the importance of thorough cross-examination in exposing potential weaknesses in expert testimony. It also places a higher burden on prosecutors to ensure that all relevant witnesses are available for questioning. Defense attorneys should remain vigilant, ready to challenge any expert opinions based on absent witnesses’ work.

The Smith v. Arizona decision reinforces the Sixth Amendment’s Confrontation Clause, particularly in cases involving forensic evidence. It underscores the principle that defendants must have the opportunity to confront and cross-examine witnesses whose factual findings form the basis of expert testimony. This ruling has significant implications for criminal trials, potentially reshaping how prosecutors present forensic evidence.

Defense attorneys should remain vigilant, ready to challenge expert testimony that relies on non-testifying analysts’ work. As courts grapple with applying Smith, we may see a shift in trial strategies and a renewed emphasis on live testimony from forensic analysts.

Ultimately, this decision strengthens the adversarial process, promoting fairness and reliability in criminal proceedings. It serves as a reminder that the Constitution’s protections extend to the increasingly complex world of forensic science, safeguarding defendants’ rights in an era of rapidly advancing technology.