William "Deep Throat" Rehnquist?

This strikes me as plausible:

I think I know who it is: Chief Justice William Rehnquist.....

Woodward has always said that he and Bernstein and Ben Bradlee won't ever reveal til he's dead. We're now told Deep Throat is quite "ill" and Bradlee says the obit's already written.

Rehnquist was a Deputy Attorney General in the "Office of Legal Counsel" from 1969-1972 under Nixon's Deputy AG, Richard Kleindienst. Rehnquist and Kleindienst were very good friends when both were lawyers in Phoenix, and Kleindienst recruited Rehnquist into the Justice Department when Nixon got elected. Rehnquist stayed three years and then Kleindienst pushed Nixon to appoint him to the Court, which happened in January of 1972. Just six months later AG John Mitchell resigned to head Nixon's re-election committee (CREEP), and Kleindienst replaced Mitchell as AG just five days before the June '72 Watergate break-in. Kleindienst resigned in 1973 along with Haldeman, Ehrlichman and Dean, but he and Rehnquist remained close.

So: we have Rehnquist in Washington throughout the relevant time frame, in the Nixon Justice Dept. for three years, presumably maintaining numerous contacts within the Administration even after he went to the Court in January '72, and he's quite ill right now. Seven of the eight clandestine meetings Woodward describes between himself & Deep Throat in the book "All The President's Men" took place on weekends, presumably a time when Rehnquist's duties to the Court would not interfere.

Not only that, but the somewhat cryptic, elliptical, low-key style of speaking that Woodward attributes to Deep Throat in the book (and so memorably recreated in the movie by Hal Holbrook) eerily mirrors the manner in which Rehnquist speaks in real life.

Woodward, incidentally, had unprecedented access to the Supreme Court for his best-selling 1975 book, "The Brethren: Inside the Supreme Court".