One strand of "Framers intent" originalist methodology looks to the legally operative acts of the Framers as putative evidence of how they construed constitutional terms.
But of course the more the actions of the Framers are seen as defining the meaning of such terms, the more the notion that the Framers themselves might have engaged in "unconstitutional" action becomes a conceptual impossibility.
Thus, Shorter Originalism: When the Framers do it that means that it is not unconstitutional.
SIDE NOTE: It's a bit unfair to pick on Dick Nixon in this regard, since others -- for example, in the executive legislative vice-presidential branch -- have adopted the same principle; Nixon's merely the one who forgot to use the inside voice. (Not that there's anything wrong with being a bit unfair.)
(The "Shorter Originalism" crack was induced by Eugene Volokh's post here.)
