Assertion of Executive Privilege Described as "Breathtakingly Broad"

As we watch our national government’s long march towards the unitary executive, it is sometimes hard to know whether to laugh or cry.
The Washington Post today has the latest from the White House on executive privilege:

Bush administration officials unveiled a bold new assertion of executive authority yesterday in the dispute over the firing of nine U.S. attorneys, saying that the Justice Department will never be allowed to pursue contempt charges initiated by Congress against White House officials once the president has invoked executive privilege.

This latest assertion of privilege is based on a 1984 Justice Department memo:

The President, through a United States Attorney, need not, indeed may not, prosecute criminally a subordinate for asserting on his behalf a claim of executive privilege. Nor could the Legislative Branch or the courts require or implement the prosecution of such an individual.

As for the law itself:

TITLE 2 > CHAPTER 6 > § 194. Certification of failure to testify or produce; grand jury action
Whenever a witness summoned as mentioned in section 192 of this title fails to appear to testify or fails to produce any books, papers, rec­ords, or documents, as required, or whenever any witness so summoned refuses to answer any question pertinent to the subject under inquiry before either House, or any joint committee established by a joint or concurrent resolution of the two Houses of Congress, or any committee or subcommittee of either House of Congress, and the fact of such failure or failures is reported to either House while Congress is in session or when Congress is not in session, a statement of fact constituting such failure is reported to and filed with the President of the Senate or the Speaker of the House, it shall be the duty of the said President of the Senate or Speaker of the House, as the case may be, to certify, and he shall so certify, the statement of facts aforesaid under the seal of the Senate or House, as the case may be, to the appropriate United States attorney, whose duty it shall be to bring the matter before the grand jury for its action. [emphasis mine]

According to the White House, a United States attorney is “may not, prosecute criminally a subordinate for asserting on his behalf a claim of executive privilege,” while the law says it is his or her “duty...to bring the matter before the grand jury.”
I may not know that much about the law, but I do have a passing familiarity with the English language, and don’t see how the administration’s assertion squares with the relevant law.
Perhaps there is someone better versed than I in these matters who could comment:

Mark J. Rozell, a professor of public policy at George Mason University who has written a book on executive-privilege issues, called the administration's stance "astonishing."
"That's a breathtakingly broad view of the president's role in this system of separation of powers," Rozell said. "What this statement is saying is the president's claim of executive privilege trumps all."

Glenn Greenwald has a sober review of the matter, in which he notes that this assertion of privilege was, not surprisingly, anonymous:

We do not know who specifically in the administration announced this obviously radical position because the Post courteously granted them a shield of anonymity to hide behind.