Optionally adding the words "so help me God" is, of course, anyone's right. These words, however, should not be a part of the official oath, where they inevitably lead to situations in which cadets are forced or coerced to say them. Therefore, the Military Religious Freedom Foundation (MRFF) has demanded that the words be removed. This, of course, has cause a media firestorm, and even proposed legislation to prevent the oath from being changed.
The defenders of "so help me God" are claiming that things like this were the intent of the founders and have deep historical roots, and, as expected are using quite a few lies about American history to support this claim -- ironically lying to defend an oath in which cadets swear not to ... um ... lie.