How in the bloody blue hell did Poe get convicted of murder? His pregnant wife was threatened by a bunch of thugs in a bar parking lot. That should have been an open-and-shut case of self defense, military training or not.
Which of course still leaves the question of why he was in a federal prison for what was basically a bar fight that got ugly, the feds would have no jurisdiction here, it's strictly as local matter and should have been in state court.
Biased anti-military judge, perhaps. His speech about how Poe is a "living weapon" and must be held to different standards than "normal" men certainly implies he has no love for soldiers.
Along with this, why did he go before a civilian court instead of a military one? Even if he had just gotten honorably discharged, he probably still would have been able to get an attorney through the Army.
Not sure about the second suggestion but I do know that in order to be sentenced federal prison you need to go to in front of a federal judge.