Why isn't this a valid defense? If he's required to do it in his role as a Senator, and the question at the hearing was if he did it in his role as part of the Trump campaign (thus the reference to being a "Surrogate") then it does in fact come down to the nature of the conversation, doesn't it?
The reason so many of us are less optimistic is because people can't resist jumping to crazy conclusions. Talking to an ambassador from another country isn't treason, that's what they're here for. As far as I understand, the question is was he doing it as a surrogate for Trump or as part of armed services committee business.
I spent eight years watching Republicans try to dance on Obama's grave ("This testimony about Benghazi will have him in jail by March!") and I always thought it was hilarious. But I'm seeing a lot of the same thing here.
The question was about anyone associated with the campaign meeting Russian officials.