Yes, a service member can be retried, but it depends on the nature of the prosecutorial misconduct and the reason for the mistrial. The Fifth Amendment’s Double Jeopardy Clause protects a person from being tried twice for the same offense. However, a mistrial is not the same as an acquittal. It is a ruling by the judge that stops the trial before a verdict is reached due to a serious error.
If the mistrial is declared because of prosecutorial misconduct, the general rule is that a retrial is permissible as long as the prosecutor did not intentionally cause the mistrial to gain a tactical advantage. For example, if a prosecutor inadvertently introduces improper evidence and the judge declares a mistrial, a new trial can usually be held. The remedy for the misconduct is starting over with a clean slate, not letting the accused go free.
However, there is a narrow exception. If a military defense attorney can prove that the prosecutor intentionally committed the misconduct with the specific purpose of goading the defense into asking for a mistrial (perhaps because the prosecutor’s case was going poorly and they wanted a “do-over”), then the Double Jeopardy Clause may bar a retrial. The attorney would have to make a motion to dismiss, and the judge would hold a hearing to determine the prosecutor’s intent. This is a very high bar to meet, but it provides a crucial protection against deliberate governmental overreach.