Actually traitor means one who has gone over to the side of the enemy. In this case he has been the enemy all along, the correct word is infiltrator, usurper, there may be an even better choice that is not occurring to me now but traitor is definitely NOT the correct term. You cannot switch to the side of the enemy if you have always been the enemy.
I see your point. Obama has certainly been working for the enemy, or if you’re religiously inclined, The Enemy, from Day One.