US senators vetting the nominee for the Supreme Court vacancy, Harriet Miers, have criticised her for giving inadequate answers to their questions.
President Bush has defended Harriet Miers against criticism
Sen Patrick Leahy, top Democrat on the Senate Judiciary Committee, said some of her replies were only a single word, seen as "incomplete to insulting".
The panel has told Ms Miers it wants more detailed information ahead of her confirmation hearing next month.
President George W Bush, who nominated Ms Miers, defended his decision.
Critics have questioned the credentials of Ms Miers - a lawyer who has never served as a judge - to sit on the Supreme Court, one of the most influential bodies in US public life.
Republican Arlen Specter, chairman of the Senate Judiciary Committee, said he and Sen Leahy had agreed the answers given by Ms Miers to the panel's questionnaire were "insufficient".
The committee has written to Ms Miers asking her to provide extra detail, particularly on her experience with constitutional issues.
Her lack of a judicial record means many questions remain over her legal experience and views.
MIERS' CAREER PATH
1985: First female president of the Dallas Bar Association
1992: First woman to head the Texas State Bar
1995-2000: Chairwoman of the Texas Lottery Commission
2001: Joins White House staff as president's staff secretary
2003: Appointed Deputy Chief of Staff
2004: Named White House counsel
However, in her defence, Sen Specter suggested the "chaotic" nature of Ms Miers' nomination process so far was down to her busy workload and factors, such as media interest, outside her control.
Ms Miers swiftly replied to the panel, saying she would "work to provide additional materials".
Questioned about Ms Miers while at a joint press conference with Palestinian leader Mahmoud Abbas, Mr Bush rebuffed the criticism.
He acknowledged that Ms Miers, a close White House aide, had emerged from a "little different process from the norm" but suggested much of the opposition was because she lacked a clear-cut record as a judge.
The process would show that she was a "competent, strong, capable woman", he said, who shared his conservative judicial philosophy.
If approved by the Senate, Ms Miers, 60, will take up the place left by Sandra Day O'Connor, considered the holder of a key swing vote on the court.
On the Republican right, some conservative groups have expressed disappointment with Ms Miers' nomination, saying they had been promised a staunchly conservative candidate.