Ryan Scoville has these thoughts at Just Security: Boehner Invites Bibi: A Closer Look at Historical Practice. From the introduction:
[In regard to] questions of original meaning and custom … I think the blogosphere has been too summary in its judgment. Ramsey emphasizes that influential members of the Washington Administration viewed the executive as a constitutionally required intermediary for official communication between Congress and foreign governments. Spiro suggests that there is no supporting practice from the Founding Era. And Bernstein states, albeit somewhat tentatively, that “direct diplomatic relations with foreign governments are exclusive in the executive.” In my view, this commentary overlooks a lot of important precedent and, in the case of Ramsey, focuses too much on the views of the Washington Administration and too little on contemporaneous understandings of the First Congress.
Professor Scoville is the author of the outstanding article Legislative Diplomacy (Michigan Law Review 2013).
Also, Peter Spiro (who started all this!) has additional thoughts at Opinio Juris: More on Boehner’s Netanyahu Invite (and What It Says About Constitutional Change). Although in theory I don't disagree with him as a descriptive matter, and perhaps not even as a normative matter, that practice can create precedents beyond the original meaning, I think he reads a bit much into this particular incident. Whether the address ultimately goes forward or not, I don't think it will be regarded as a happy precedent.
Posted at 4:15 PM