I actually don’t know the details of the specific crimes. Eg if you’re a soldier and you post on Facebook that you’re about to go on a raid to depose a head of state, that’s presumably a secrecy violation you would be punished severely for. The insider trading can be like this too in that you’re improperly using the information you are privy to due to your being an insider. If you’re a congressperson and you tweet that the government is about to do such a raid, I don’t know what the legality of that is – perhaps you have some kind of privilege to reveal these things and any censure must happen politically (eg impeachment, losing elections, etc) rather than legally. I don’t know what the rules for insider trading would then be – legislators are not insiders in the way that soldiers are.

Ignoring the moral argument, it isn’t all that clear to me that this would actually be a crime for a legislator under US securities law. It may be that new laws would be required to be able to punish legislators for this kind of behaviour.