“Suffice it to say” is the subjunctive form of “it suffices to say.” E.g.:
o “Suffice it to say that the plotters, once their plan has been set into motion, aren’t content to leave well enough alone.” Janet Maslin, “‘Deathtrap’ with Michael Caine,” N.Y. Times, 19 Mar. 1982, at C8.
o “When her students were asked how they liked working with her, suffice it to say that they gushed.” Natalie Angier, “Scientist at Work,” N.Y. Times, 30 May 1995, at C1.
The phrase is sometimes wrongly metamorphosed into *"suffice to say," without the “it” — e.g.: “In a following chapter we shall have much to say about reasoning and inference, but for now suffice to say [read ‘suffice it to say’] that it is easier to argue a case after it has been adequately elaborated and illustrated.” V.A. Howard & J.H. Barton, Thinking on Paper 59 (1986). Maybe the writers were concerned with the number of “its” already in the sentence — a valid concern. But they could have fixed the problem in some other way. (A possible revision: “Later, we’ll have something to say about reasoning and inference. But for now, suffice it to say that you can more easily argue a case after adequately elaborating and illustrating your points.”)
Language-Change Index — *"suffice to say" for “suffice it to say”: Stage 2.
*Invariably inferior forms.
