God, the intersection of what it means to be a member of some Official Public Machinery vs building your Twitter brand of hot takes is such a quagmire. I do not envy anyone trying to untangle this.

Normally I would say: this is one of those things where all the work is done by norms and other social machinery, not by laws, there is no way to legislate all the edge cases.

But then we have the Trump presidency, which, whatever else you say about it, could be viewed as one large exploit of that idea. If it is not strictly illegal, there is no countervailing force for that guy. Presumably other politicians behave in similar ways, just less egregiously.