Assuming that you wisely exercised your right to remain silent during the trial, how would you "tell" them anything? How would you provide documents? It is the process of "discovery" that permits such evidence to find itself before the court.
What is it about the charges against Lakin that makes you want to deny him the ability to mount a defense? It's a serious matter for a military officer to doubt the validity of his orders. If it is found that the orders were lawful, because Obama is eligible, just exactly what harm is done? Lakin will be punished, other officers will be cautioned by his unfortunate experience, and life will go on. What is it you fear?
I would NOT have remained silent if tried, because I knew exactly why the orders were illegal. And yes, the defense provides documentation all the time.