"Ms. Miers has absolute immunity from compelled congressional testimony as to matters occurring while she was a senior adviser to the president," White House Counsel Fred Fielding wrote in a letter to Miers' lawyer, George T. Manning.
Manning, in turn, notified committee chairman John Conyers, D-Mich., that Miers would not show up Thursday to answer questions about the White House role in the firings of eight federal prosecutors over the winter.
Conyers, who had previously said he would consider pursuing criminal contempt citations against anyone who defied his committee' subpoenas, revealed the letters after former White House political director Sara Taylor testified Wednesday before the Senate Judiciary Committee.
Conyers said of Miers, Mr. Bush's former White House lawyer, "As a former public official and officer of the court, Ms. Miers should be especially aware of the need to respect legal process, and we expect her to appear before the committee tomorrow as scheduled."
Fielding said the Justice Department had advised the White House that Miers had absolute immunity from compelled congressional testimony.
"The president has directed her not to appear at the House Judiciary Committee hearing on Thursday, July 12, 2007," Fielding wrote.
Taylor told senators she never talked to President Bush about the firing of U.S. Attorneys and doesn't think he had anything to do with the decisions, but she wouldn't answer most of the panel's specific questions, citing the president's directive not to, reports CBS News' Bob Fuss.
"I did not attend any meetings with the president where that matter was discussed," Taylor said under stern questioning by Senate Judiciary Committee Chairman Patrick Leahy.
When asked more broadly whether Mr. Bush was involved in any way in the firings, Taylor said, "I don't have any knowledge that he was."
Taylor, who left the White House eight weeks ago for reasons she said were unrelated to the firings, was treading a rough line between obeying Mr. Bush's order not to reveal internal White House deliberations and responding to a congressional subpoena compelling her to do so. Her lawyer, Neil Eggleston, sat at the witness table to advise her.
"I'm trying to be consistent and perhaps have not done a great job of that," Taylor said. "I have tried."
The committee's ranking Republican, Sen. Arlen Specter, said that may not be enough to protect her from a contempt citation for failing to answer many of the committee's questions.
"There's no way you can come out a winner," said Specter, R-Pa. "You might have been on safer legal ground if you'd said absolutely nothing."
As for the prospects of pursuing a criminal citation for contempt of Congress, Leahy said only, "That's a decision yet to be made."
The exchange was part of proceedings that were as much about the ongoing dispute over what information the White House can keep secret as it was about the stated topic — the firings over the winter of eight U.S. attorneys.
Loyal to Mr. Bush even outside the White House, Taylor said she was trying not to answer questions that might violate the president's claim of executive privilege. At one point she reminded the committee that as a commissioned officer, "I took an oath and I take that oath to the president very seriously."