What makes it legal is that it wasn’t classified - not that Comey did it through a third party. Or at least that’s Comey’s reasoning. Had the memo been classified then it would have clearly been illegal. And is there ANYONE who believes this is the only thing Comey leaked? ~crickets~
Someone posted elsewhere that Comey had previously testified that he hadn’t leaked certain information. The point I’m making is that a hair-splitting legalist like Comey would take very special care not to implicate himself. If he described leaking an item publicly (he did) it would have been done in such a way as to let him off the hook.
I think it could be illegal since it was for the purpose of causing the hiring of a special prosecutor which infers that there is a crime involved.