If that's the case, why hasn't there been an executed spy since Julius and Ethel Rosenberg in 1951 in the U.S.? As for Snowden, his stated "cause" was to inform the U.S. population, which isn't "technically" aiding the enemy. For execution to be on the table, the government would have to prove that he knowingly and willingly meant the information to aid the enemy. It's no different than if some dumb private tooks pictures of his base in Afghanistan and posted them on instagram to detail the "horrors" of his deployment. Did he compromise his security? Hell yes! Did he willingly aid the enemy? That's for the UCMJ to decide, but while UCMJ code is MUCH more strict than civilian law, it is VERY unlikely he would face a firing squad for such actions. In this case, Snowden doesn't fall under UCMJ, so it stands to reason it would be almost impossible for the U.S. to find he "willingly" aided the enemy. which is why you haven't seen even ONE spy executed in the last 60 years.