Maybe this will help clear things up...
Kerry was separated from active duty in 1970... before the congressional testimony and meeting with the north vietnamese
http://www.johnkerry.com/about/john_..._timeline.html
but wasn't granted his discharge until 1978.
http://www.johnkerry.com/pdf/jkmilse...om_Reserve.pdf
Kerry was under the direct authority of the UCMJ until 1978. It's kind of a legal quagmire... the definitions for the words in context are obscure. the site above lists kerry in 1970 as a "Registrant who has completed service." this designation isn't about active duty or reserve status, it is to classify kerry as a person who is ineligible for the draft through Selective Service because he has already fulfilled his service obligations.
even so, kerry was undoubtedly a commissioned reserve naval officer through 1978. he joined the veteran's groups and met with the enemy under those legal conditions. the poster above me (rat) hit the nail on the head. this is a clear violation of the UCMJ and certainly a breech of discipline in a legal sense. granted, it isn't the same as if he had done it on active duty... but i'm certain the then mr. kerry was fully aware of his reserve status and the legal obligations that it entails.
of course, no one cares...