If he was supporting the SOG guys, he would have had a security oath obligation to notify the FBI he was going to Paris to meet with the communists. I am sure that RM Nixon would have loved to have had him arrested on that. I don't think anyone is well connected enough not to at least get charged with violating his security oath (10yrs-$10,000). Although as a service member, he could get the death penalty in time of war.
The entire story smells big time.
Correct me MACVSOG68 if I am wrong. (I just worked on the cryto gear)
Doubt if anyone would have prosecuted him at that time, but yes, the whole story is nothing but BS.