The ever pithy Prof. Colin Miller has an excellent post about issues under Mil. R. Evid. 1004.
The best evidence rule is now in Mil. R. Evid. 1004. The rule requires originals, not and/or, unless the original is lost or destroyed. So, when you object make that distinction clear. Prosecutors and military judges often conflate the rule into, a it doesn’t matter rule. Before the prosecution can use copies they have to establish that the original is lost or destroyed.
Now, what happens if the original is lost or destroyed due to the fault of the possessor of the original – for example the victim destroys text messages or other information, in bad faith.
That’s the nub of Prof. Miller’s piece: “my conclusion in that in a criminal trial, both the alleged victim of the crime and the prosecution should be considered the proponent of the evidence Federal Rule of Evidence 1004, meaning that misconduct by either should preclude the admission of secondary evidence.”