Orders are assumed to be lawful unless they obviously are in conflict with established law.
Given that Obama is accepted as President by the Congress & US Supreme Court, there is no obvious reason why his orders to deploy are illegal.
An officer is not required to prove an order is legal. And a suspicion that they may not be legal is insufficient grounds for disobeying. On several occasions, I told my Commander that if he would put his orders in writing and run them past legal, I’d obey them. On those occasions, the refusal of my Commander to do so left me free to refuse, which I did. And yes, I took some personal loss in career from continuing to be evaluated by someone whose orders I had refused to obey.
So, a man whose father was a Kenyan subject is automatically not eligible to serve as COC of the US military. That means he can OBVIOUSLY not be handing down legal orders.
Enuff said.