All military personnel sign an enlistment contract,click> Form DD 4, that spells out one's obligations to the US branch of service. You will notice that there is no "having to agree with or like it clause". Determining the legality of the conflict in question is way beyond a Lieutenant's pay grade. The correct way to respond is to follow his orders and file his greivance. His admirers and supporters will be able to mail their correspondence to him at Fort Leavenworth, Kansas (military prison) after his military courts martial has concluded, because that is where he will end up.