See, this strikes me as a bad idea on palpys part. "Hey, im a sith, hes a sith, sith are known for apprentices betraying and killing their masters once they stop getting stronger..... ill make my apprentice supreme commander of the entire galaxy's military. I dont foresee anything bad possibly happening through that." Didnt palpatine betray and kill his OWN master way back in the day? Seems like he might have thought that decision through a bit better.