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Expert testimony can violate the Confrontation Clause when a substitute witness conveys an absent analyst’s testimonial statements and the jury must accept those statements as true to credit the opinion. This article explains the Supreme Court’s clarification in Smith v. Arizona, its relationship to earlier forensic-evidence cases, and practical considerations for evaluating whether an expert’s work is genuinely independent.
In June 2024, the U.S. Supreme Court addressed a scenario that can arise in criminal cases involving forensic evidence. The analyst who performed the lab testing does not testify, but the prosecution still seeks to present the lab results through another witness. So the State calls a different expert to take the stand and explain the results “based on” the absent analyst’s file.
That is not just a scheduling issue. Handled the wrong way, it can raise a Sixth Amendment Confrontation Clause problem. In practice, that can reshape confrontation briefing, motion strategy, and trial planning.
This guide explains what the Court clarified in Smith v. Arizona, why “basis” testimony can still trigger confrontation concerns, and how attorneys can recognize the risk early.
The Sixth Amendment’s Confrontation Clause gives a criminal defendant the right to confront the witnesses against him.
In cases like Smith, courts ask two core questions:
How testimony is presented matters. Even when lawyers describe information as “background” or “basis,” the judge still has to ask what the jury is being asked to believe and why. Labels do not control the analysis.
Arizona police seized suspected drugs and sent them to a crime lab. Analyst Elizabeth Rast performed the testing and generated typed notes and a signed report. By the time of trial, Rast did not testify.
The State called another analyst, Gregory Longoni. He did not perform the testing. He reviewed Rast’s file and relied on her records. As part of his expert opinion, he walked the jury through Rast’s notes and report in detail before giving his “independent opinion.”
Smith objected. The core argument was straightforward: if the State wanted the jury to rely on Rast’s case-specific assertions and recorded results to prove guilt, then the Confrontation Clause required the State to present Rast for cross-examination, not a substitute witness.
Arizona courts upheld the conviction by treating Rast’s statements as “basis” material supporting Longoni’s opinion, rather than as statements introduced for their truth.
In June 2024, the U.S. Supreme Court addressed a scenario that can arise in criminal cases involving forensic evidence. The analyst who performed the lab testing does not testify, but the prosecution still seeks to present the lab results through another witness. So the State calls a different expert to take the stand and explain the results “based on” the absent analyst’s file.
That is not just a scheduling issue. Handled the wrong way, it can raise a Sixth Amendment Confrontation Clause problem. In practice, that can reshape confrontation briefing, motion strategy, and trial planning.
This guide explains what the Court clarified in Smith v. Arizona, why “basis” testimony can still trigger confrontation concerns, and how attorneys can recognize the risk early.
The Sixth Amendment’s Confrontation Clause gives a criminal defendant the right to confront the witnesses against him.
In cases like Smith, courts ask two core questions:
How testimony is presented matters. Even when lawyers describe information as “background” or “basis,” the judge still has to ask what the jury is being asked to believe and why. Labels do not control the analysis.
Arizona police seized suspected drugs and sent them to a crime lab. Analyst Elizabeth Rast performed the testing and generated typed notes and a signed report. By the time of trial, Rast did not testify.
The State called another analyst, Gregory Longoni. He did not perform the testing. He reviewed Rast’s file and relied on her records. As part of his expert opinion, he walked the jury through Rast’s notes and report in detail before giving his “independent opinion.”
Smith objected. The core argument was straightforward: if the State wanted the jury to rely on Rast’s case-specific assertions and recorded results to prove guilt, then the Confrontation Clause required the State to present Rast for cross-examination, not a substitute witness.
Arizona courts upheld the conviction by treating Rast’s statements as “basis” material supporting Longoni’s opinion, rather than as statements introduced for their truth.
Justice Kagan wrote the Court’s opinion. The Court focused on a practical point that drives many evidentiary disputes.
If an expert conveys an absent analyst’s statements in support of an opinion, and those statements support the opinion only if they are true, then the statements are effectively being used for their truth. Calling them “basis” evidence does not change what the jury is being asked to do.
For example, imagine a substitute expert repeats an absent analyst’s recorded result and then gives an “independent” identification opinion. If the opinion matters only if that recorded result is true, then the jury has to treat the absent analyst’s statement as true to credit the opinion. In that situation, the testimony is not neutral background. It is a pathway for the absent analyst’s case-specific statements to reach the jury.
The takeaway is simple: “basis” is not a workaround. Courts still have to evaluate what the testimony is doing in front of the jury.
After clarifying that “basis” labeling does not automatically avoid the “for its truth” problem, the Court turned to the next question: whether the absent analyst’s statements were testimonial.
The Court did not definitively decide testimonial status on the record before it. Instead, it vacated and remanded so the state court could address whether the statements were testimonial, and also whether the defendant forfeited his right to confrontation by his own conduct, a separate doctrine that could affect the analysis depending on how the record developed.
For litigators, that procedural posture matters. On remand, the testimonial analysis turns on record-specific details about the statements, their purpose, and how they relate to a future criminal proceeding.
Smith follows the Supreme Court’s broader Confrontation Clause cases involving statements used as substitutes for live testimony.
What Smith adds is clarity on a common argument. A party cannot avoid confrontation by arguing, in effect, “this is only the basis.” The judge still has to evaluate what the testimony asks the jury to accept as true.
You will also see Williams v. Illinois cited in this area. Williams produced multiple opinions and did not yield a single majority rationale on the “not for its truth” basis theory, which is part of why the issue resurfaced in Smith. Smith reinforces that the analysis stays grounded in what the jury must believe, not in the label attached to the testimony.
The points below are practice-oriented. They are not new legal tests. They are ways attorneys and experts can apply the principles the Supreme Court discussed in Smith and related cases.
A practical screening question is simple: would the jury have to believe the absent analyst’s statements to trust the opinion?
As a practical matter, courts are less likely to see a confrontation problem when the testifying expert can reach conclusions without relaying the absent analyst’s case-specific statements.
Examples can include situations where the testifying expert performs new testing, or conducts a genuine re-analysis of raw data and can explain the reasoning without repeating the absent analyst’s recorded results as proof.
Even then, the confrontation analysis still depends on what statements are conveyed to the jury. Testimony tends to look less independent when the witness mainly summarizes what another analyst did, observed, or concluded, and the opinion depends on those details being correct.
Does the Confrontation Clause always require the original forensic analyst to testify?
Not always. The main risk is when the prosecution relies on an absent analyst’s testimonial statements as proof and the defense has no chance to cross-examine that analyst.
Can the prosecution use a substitute expert if the substitute offers an “independent opinion”?
A label is not enough. If the opinion depends on the jury accepting the absent analyst’s case-specific assertions as true, confrontation concerns can still arise.
Did Smith v. Arizona definitively rule that the testimony in that case violated the Confrontation Clause?
The Court clarified that when an absent analyst’s statements are conveyed to support an opinion and they matter only if true, the statements are being used for their truth. The Court did not finally resolve whether those statements were testimonial. It vacated and remanded for further proceedings, including that analysis and any forfeiture issues.
What does “testimonial” mean in this setting?
“Testimonial” is fact-specific. In this setting, courts often focus on the statement’s primary purpose and how it relates to a future criminal proceeding.
How should attorneys vet forensic experts to reduce confrontation problems?
Start with task-level accountability. Confirm who performed the testing, who recorded the key case-specific results, and whether the proposed witness can explain the opinion without repeating an absent analyst’s assertions as proof.
Justice Kagan wrote the Court’s opinion. The Court focused on a practical point that drives many evidentiary disputes.
If an expert conveys an absent analyst’s statements in support of an opinion, and those statements support the opinion only if they are true, then the statements are effectively being used for their truth. Calling them “basis” evidence does not change what the jury is being asked to do.
For example, imagine a substitute expert repeats an absent analyst’s recorded result and then gives an “independent” identification opinion. If the opinion matters only if that recorded result is true, then the jury has to treat the absent analyst’s statement as true to credit the opinion. In that situation, the testimony is not neutral background. It is a pathway for the absent analyst’s case-specific statements to reach the jury.
The takeaway is simple: “basis” is not a workaround. Courts still have to evaluate what the testimony is doing in front of the jury.
After clarifying that “basis” labeling does not automatically avoid the “for its truth” problem, the Court turned to the next question: whether the absent analyst’s statements were testimonial.
The Court did not definitively decide testimonial status on the record before it. Instead, it vacated and remanded so the state court could address whether the statements were testimonial, and also whether the defendant forfeited his right to confrontation by his own conduct, a separate doctrine that could affect the analysis depending on how the record developed.
For litigators, that procedural posture matters. On remand, the testimonial analysis turns on record-specific details about the statements, their purpose, and how they relate to a future criminal proceeding.
Smith follows the Supreme Court’s broader Confrontation Clause cases involving statements used as substitutes for live testimony.
What Smith adds is clarity on a common argument. A party cannot avoid confrontation by arguing, in effect, “this is only the basis.” The judge still has to evaluate what the testimony asks the jury to accept as true.
You will also see Williams v. Illinois cited in this area. Williams produced multiple opinions and did not yield a single majority rationale on the “not for its truth” basis theory, which is part of why the issue resurfaced in Smith. Smith reinforces that the analysis stays grounded in what the jury must believe, not in the label attached to the testimony.
The points below are practice-oriented. They are not new legal tests. They are ways attorneys and experts can apply the principles the Supreme Court discussed in Smith and related cases.
A practical screening question is simple: would the jury have to believe the absent analyst’s statements to trust the opinion?
As a practical matter, courts are less likely to see a confrontation problem when the testifying expert can reach conclusions without relaying the absent analyst’s case-specific statements.
Examples can include situations where the testifying expert performs new testing, or conducts a genuine re-analysis of raw data and can explain the reasoning without repeating the absent analyst’s recorded results as proof.
Even then, the confrontation analysis still depends on what statements are conveyed to the jury. Testimony tends to look less independent when the witness mainly summarizes what another analyst did, observed, or concluded, and the opinion depends on those details being correct.
Does the Confrontation Clause always require the original forensic analyst to testify?
Not always. The main risk is when the prosecution relies on an absent analyst’s testimonial statements as proof and the defense has no chance to cross-examine that analyst.
Can the prosecution use a substitute expert if the substitute offers an “independent opinion”?
A label is not enough. If the opinion depends on the jury accepting the absent analyst’s case-specific assertions as true, confrontation concerns can still arise.
Did Smith v. Arizona definitively rule that the testimony in that case violated the Confrontation Clause?
The Court clarified that when an absent analyst’s statements are conveyed to support an opinion and they matter only if true, the statements are being used for their truth. The Court did not finally resolve whether those statements were testimonial. It vacated and remanded for further proceedings, including that analysis and any forfeiture issues.
What does “testimonial” mean in this setting?
“Testimonial” is fact-specific. In this setting, courts often focus on the statement’s primary purpose and how it relates to a future criminal proceeding.
How should attorneys vet forensic experts to reduce confrontation problems?
Start with task-level accountability. Confirm who performed the testing, who recorded the key case-specific results, and whether the proposed witness can explain the opinion without repeating an absent analyst’s assertions as proof.
Expert Witness Guides
Expert Witness Guides