The Texas lawyer nominated to the US Supreme Court by President George W Bush, Harriet Miers, has withdrawn as a nominee to the court.
Harriet Miers' nomination has placed Mr Bush in the spotlight
Ms Miers, who has served as White House counsel for Mr Bush but has no judicial experience, has come in for criticism from both Democrats and Republicans.
She was reprimanded by Senators for giving "incomplete to insulting" answers to written questions.
The withdrawal of Ms Miers is seen as a significant blow to Mr Bush.
Her decision comes amid tense times for the White House, which is currently waiting for news on possible indictments of senior administration figures in connection with a CIA leak case.
Mr Bush's approval ratings have meanwhile been plummeting, and his apparent inability to push his choice through is thought likely to raise fresh concerns as to what he can achieve in his second term.
Ms Miers' nomination had drawn criticism from both sides of the political divide.
Conservative Republicans were sceptical of Ms Miers' suitability for the court on ideological grounds.
Several questioned her attitudes on the touchstone issue of abortion, while others doubted her understanding of constitutional law.
Democrat opponents accused the president of cronyism, pointing to personal memos sent during Mr Bush's days as governor of Texas as evidence that her friendship with the president was her chief qualification for the job.
Mr Bush had indeed made much of his personal relationship with Ms Miers, and had asked the country to trust him in his choice of a relative unknown.
The BBC's Matt Frei, in Washington, says the president has rarely spoken in such personal terms about a nominee, but neither the country, the conservatives in the Republican party, or the Democrats were prepared to back him.
It will now be extremely tough for Mr Bush to find someone who is acceptable to all sides, our correspondent adds.
In a letter confirming her decision to withdraw from the nomination process, Ms Miers wrote that continuing to seek Senate approval would prove to be a burden on the White House.
It would not be in the interests of the US to reveal details of her work within the White House, she added.
Mr Bush praised Ms Miers for her decision, which he said was motivated by a desire not to allow Senators access to confidential White House documents.
"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," Mr Bush said.
The president said he would fill the Supreme Court seat, due to be vacated by Sandra Day O'Connor, in "a timely manner".