An Article 32 preliminary hearing is the gateway to a general court-martial, but it is a narrower proceeding than many people expect. After Congress amended Article 32 in the National Defense Authorization Act for Fiscal Year 2014 and the President revised Rule for Courts-Martial (RCM) 405, the hearing changed from a broad investigation into a limited probable-cause and disposition review. That shift directly shapes whether, and how, expert testimony fits into the proceeding. The short answer is that expert testimony is not categorically barred, but the structure of the modern Article 32 hearing makes live expert testimony unusual and tightly constrained.
What the modern Article 32 hearing decides
The preliminary hearing officer, often called the PHO, has a defined and limited mission. The officer determines whether there is probable cause to believe an offense was committed and that the accused committed it, whether the convening authority has court-martial jurisdiction over the offense and the accused, the proper form of the charges, and a recommendation as to disposition. The hearing is not a discovery device and not a trial. Because the questions are limited, the evidence and witness examination are limited to matters relevant to those determinations. If a party offers material outside that scope, the preliminary hearing officer is supposed to halt it.
This narrowing is the single most important factor when evaluating expert testimony. A topic that would be central at trial, such as the reliability of a forensic method or the interpretation of a complex medical finding, may simply be unnecessary to decide whether probable cause exists.
How evidence reaches the hearing officer
At a preliminary hearing the government can meet its burden largely on paper. The hearing officer may consider sworn or unsworn statements, reports, and other documents, including matters that would be inadmissible hearsay at a court-martial. Witnesses do not have to appear live for their information to be considered. This is a deliberate design choice: the hearing tests probable cause, not the ultimate admissibility or weight of evidence.
For expert input, this means an expert’s written report or affidavit can be presented to the hearing officer without the expert ever testifying in person. In many cases that is how expert material enters an Article 32 hearing, through documents rather than live testimony.
When can an expert actually testify live?
Live testimony at a preliminary hearing turns on relevance and availability. A witness, including an expert, is generally produced to testify only if the witness is relevant to the limited issues, reasonably available, and not cumulative. The hearing officer weighs the significance of the testimony against the difficulty and expense of producing the witness. Because experts are often retained, located off the installation, or otherwise costly to produce, and because their opinions frequently bear on trial-level questions rather than probable cause, requests for live expert testimony are scrutinized closely.
The preliminary hearing officer also exercises a gatekeeping role borrowed from the evidentiary rules. In applying the limited evidentiary protections that do operate at the hearing, the role assigned to the military judge under those rules is performed by the hearing officer. So the hearing officer can decline to hear testimony that strays beyond the scope of the proceeding, including expert testimony that addresses matters not needed to resolve probable cause, jurisdiction, form of charges, or disposition.
Practical examples
Consider a case where the charged conduct depends on whether a substance was a controlled substance. A laboratory report may establish probable cause on its own, and the hearing officer can rely on that document. Live testimony from the chemist may add little to the probable-cause analysis even though it could be vital at trial.
Now consider a case where the defense contends the accused lacked mental responsibility, and a sanity board or examiner has produced findings. Those findings can be submitted as documents. Whether the hearing officer permits the examiner to testify live depends on whether that live testimony is relevant to a decision the officer must make and whether the witness is reasonably available. Often the documentary findings suffice for the limited purpose of the hearing.
What this means for the defense and the government
For the defense, the takeaway is to be realistic about goals. The Article 32 hearing is not the place to litigate the full reliability of expert methods through live cross-examination. Defense counsel can still submit favorable expert reports, can request a relevant and reasonably available expert when the testimony genuinely bears on probable cause or disposition, and can use the hearing to test the strength of the government’s showing. Counsel can also preserve issues for trial, where the Military Rules of Evidence apply in full and where challenges such as those under the rules governing expert opinion and scientific reliability are properly raised.
For the government, expert material is usually offered to support probable cause, frequently through reports. The government need not produce live expert testimony to meet its modest burden.
Bottom line
Expert testimony is allowed at an Article 32 preliminary hearing, but it is the exception rather than the norm in live form. The hearing’s limited purpose, the relaxed treatment of documentary evidence, and the requirement that any witness be relevant, reasonably available, and not cumulative combine to favor written expert submissions over live testimony. When live expert testimony is genuinely necessary to the hearing officer’s limited determinations, it can be permitted, subject to the officer’s gatekeeping authority. The deeper fights over an expert’s qualifications, methods, and conclusions are generally reserved for the court-martial itself, where the full Military Rules of Evidence govern.
Disclaimer
This article is provided strictly for general educational and informational purposes. It is intended to explain how the Uniform Code of Military Justice (UCMJ), the Rules for Courts-Martial, the Military Rules of Evidence, and related military administrative processes work as a matter of public legal education. It does not constitute legal advice, a legal opinion, or a recommendation about any particular case, and it is not a substitute for advice from a qualified military defense attorney who can evaluate the specific facts and command, service, and jurisdictional circumstances involved.
Reading this article, or contacting any website on which it appears, does not create an attorney-client relationship between the reader and any law firm, attorney, or author. Every court-martial, nonjudicial punishment action, administrative separation, and security-clearance matter turns on its own facts, the charged articles, the convening authority, the service branch, and the evidence, and outcomes vary widely from one case to another.
Military law also changes over time. The Military Justice Act of 2016 (effective January 1, 2019) and subsequent National Defense Authorization Acts renumbered and rewrote many punitive articles, revised the Article 32 preliminary hearing, and altered sentencing, clemency, and appellate procedures. Statutes, regulations, executive orders, the Manual for Courts-Martial, and decisions of the service Courts of Criminal Appeals and the Court of Appeals for the Armed Forces may have been amended, superseded, or reinterpreted after this article was written, and article numbers or procedures cited here may have changed.
For these reasons, no reader should act or decline to act based on this content without first consulting a licensed attorney experienced in military justice about their own situation. The author and publisher make no warranty, express or implied, as to the accuracy, completeness, timeliness, or current applicability of the information provided, and disclaim any liability for any action taken or not taken in reliance on it. If you are facing investigation, charges, or an adverse administrative action, time limits may apply, and you should seek qualified counsel promptly.