The Article 32 preliminary hearing is the gateway between a preferred charge and referral to a general court-martial. It is presided over by a preliminary hearing officer, or PHO, who is a neutral official rather than an advocate for either side. When the government and the defense each present expert opinions that point in opposite directions, the PHO has to make sense of that conflict without conducting a full trial. The way a PHO handles dueling experts reflects the limited but real purpose of the hearing and the unusual evidentiary rules that govern it.
The narrow purpose of the Article 32 hearing
Article 32, codified at 10 U.S.C. 832, requires a preliminary hearing before a charge may be referred to a general court-martial. The hearing is not a trial and it is not designed to resolve guilt. Its purpose is limited and statutory. The PHO determines whether the specification states an offense under the UCMJ, whether there is probable cause to believe the accused committed the charged offense, whether the convening authority has court-martial jurisdiction over the accused and the offense, and what disposition the PHO recommends.
Probable cause is the operative standard, and it is far lower than proof beyond a reasonable doubt. This single fact shapes everything about how conflicting expert opinions are treated. The PHO is not asked to decide which expert is correct. The PHO is asked whether, taking the evidence as a whole, there is probable cause to believe an offense occurred and that the accused committed it.
The PHO as a neutral official
Whenever practicable, the PHO is a certified judge advocate. When that is not practical, the convening authority may detail an impartial commissioned officer. Either way, the PHO is meant to be neutral and does not represent the government or the defense. The PHO hears the evidence, rules on questions of admissibility within the limited rules that apply, and submits a written report with findings and a disposition recommendation to the convening authority.
That neutral posture matters when experts conflict. The PHO is not a partisan trying to vindicate one side’s expert. The PHO weighs both presentations against the modest probable-cause threshold.
Relaxed rules of evidence change the picture
A defining feature of the Article 32 hearing is that the Military Rules of Evidence largely do not apply. With limited exceptions for privileges, certain interrogation rules, and the rape-shield protections of MRE …