It is NOT up to this soldier to decide what orders he is or is not going to follow, especially given that the deployment orders are both lawful and appropriate.
What if it was an order to execute American civilians?
Or to fire upon Tea Party protesters?
One of the nice things about the UCMJ is that you get to defend your actions under it, it isn't a case of if you are charged, you are automatically guilty, despite what people like John Murtha have tried to ram down our throats.
But it's not.