"if I could prove someone broke their oath with knowledge, what is the legal punishment offered?" I think you answered your own question. It depends on who tha

"if I could prove someone broke their oath with knowledge, what is the legal punishment offered?" I think you answered your own question. It depends on who that person is and whether the people in charge like what he or she does. Manning gets 35 years while Cheney goes free. The answer, to be clear, is impossible to know. When charges and trials are dished out arbitrarily like this, the idea of the rule of law becomes completely laughable. It simply boils down to arbitrary persecution of people for arbitrary reasons, no different than a king or other authoritarian tyrant's rule.