She notified President Bush of her decision Wednesday night and submitted a letter Thursday thanking Mr. Bush for his support, but adding, "I am concerned that the confirmation process presents a burden for the White House and our staff that is not in the best interests of the country."
President Bush, saying he reluctantly would accept Miers' request, added it was apparent that Senate demands for internal memos prepared by Miers as White House counsel would undermine the executive branch.
"It is clear that senators would not be satisfied until they gained access to internal documents concerning advice provided during her tenure at the White House -- disclosures that would undermine a president's ability to receive candid counsel," President Bush said. "Harriet Miers' decision demonstrates her deep respect for this essential aspect of the constitutional separation of powers -- and confirms my deep respect and admiration for her."
Miers' nomination had been the subject of intense criticism from both sides of the political aisle since the president announced her selection Oct. 3. The complaints surrounded her lack of legal credentials and longtime association with President Bush.
Conservatives voiced uncertainty about her political ideologies, and others cited her reluctance to state her opinions on even established court precedents as a cause for concern.
On Capitol Hill, there was meager support among Republicans and it appeared her nomination may not receive the 51 votes needed in the Senate for passage.
Sen. Trent Lott, R-Miss., told Fox News that Miers had been the wrong person for the job.
"Let's move on," he said. "In a month, who will remember the name Harriet Miers."
Democrats offered a more mixed reaction with some saying she had failed to demonstrate the qualities needed on the court and others blaming conservative Republicans for derailing the nomination.
"The radical right wing of the Republican Party killed the Harriet Miers nomination," said Senate Minority Leader Harry Reid, D-Nev., who had recommended Miers to the president.
The president said that with her withdrawal, Miers would remain White House counsel. He did not indicate when he may announce a successor to Associate Justice Sandra Day O'Connor, who announced her retirement earlier in the year once a replacement was found.
Along with Miers, speculation had focused on Bush loyalists Attorney General Alberto Gonzales and corporate lawyer Larry Thompson, who served as deputy attorney general during Mr. Bush's first term.
Other candidates frequently mentioned include conservative federal appeals judges J. Michael Luttig, Priscilla Owen, Karen Williams, Alice Batchelder and Samuel Alito; Michigan Supreme Court justice Maura Corrigan; and Maureen Mahoney, a well-respected litigator before the high court, reported the Associated Press.