Trump defenders have advanced a two-part argument to justify pre-inauguration conversations with Russia. Their first, a legal claim, concerns the Logan Act, which makes it a crime for unauthorized citizens to negotiate with foreign governments that have a dispute with the United States. Trump defenders note, accurately, that its broad sweep has left it in a legal no man’s land. The Logan Act has almost never been used. The special counsel in charge of the Russia probe, Robert Mueller, would find it difficult to dust it off for this situation.