While character letters from a service member’s chain of command can be very valuable, there are significant limitations on their use as evidence at a court-martial, particularly during the findings (guilt or innocence) phase. The primary limitation is the rule against hearsay. A letter is an out-of-court statement offered to prove the truth of its contents (i.e., that the soldier has a good character), and it is generally inadmissible. The proper way to introduce character evidence is through live, in-person testimony.
A military defense attorney should call the members of the chain of command as live witnesses. During the findings phase, these witnesses can testify about their opinion of the accused’s reputation for a “pertinent character trait,” such as peacefulness in an assault case or truthfulness in a larceny case. They cannot simply offer a broad statement that the accused is a “good soldier.” The testimony must be tailored to a specific, relevant character trait.
During the sentencing phase, after a conviction, the rules are much more relaxed. At this point, written character letters of support from the chain of command are generally admissible. The attorney will gather as many strong letters as possible from commanders, NCOs, and peers to present to the panel as mitigation evidence. These letters can be very persuasive in arguing for a more lenient sentence, but for the main part of the trial, live testimony is the required method.