The form of address is part of the detailed memorandum of understanding between the two camps, according to the sources familiar with the document. Such MOUs detail specifics ranging from how footage of the debates can be used to podium placement, and so forth. […]Or maybe it was because Biden had originally planned to refer to the good congresscritter by several other far more colorful titles, but the two camps eventually negotiated down to the more neutral "mister"? I like that theory just as well.
The sources did not spell out with precision why "mister" was preferable to "congressman," but it is almost certainly because of the low approval ratings overall of Congress.
Alas, there is no word on whether Congressm—sorry, Mister Ryan's many, many contributions to the current debacle that passes for government are allowed to be mentioned. We will know soon enough.
We'll start liveblogging/livetweeting as soon as the debate starts. Or, if you prefer: