US Chief Justice nominee John Roberts has said he would be unlikely to overturn court rulings that give women the right to have an abortion.
Pro-choice groups feel Roberts might not be sympathetic
Mr Roberts, a Roman Catholic, told the committee examining his nomination that the 1973 ruling legalising abortion was "settled as a precedent of the court".
He denied his faith would influence his decisions if he was chosen for the job.
President Bush nominated Mr Roberts to be the country's top judge after the death of William Rehnquist this month.
Correspondents say the Senate is expected to back Mr Roberts, 50.
Asked about the court's landmark ruling on the issue of abortion, Roe vs Wade, Mr Roberts called it a "very important consideration".
"There's nothing in my personal views based on faith or other sources that would prevent me from applying the precedent of the court faithfully under the principles of stare decisis," he said, referring to the legal concept by which courts are bound by previous court decisions.
Born in Buffalo, raised in Indiana
Graduated from Harvard in 1979
Was clerk to Chief Justice Rehnquist and then served in the Reagan administration
Serves on the District of Columbia appeals court
Has argued before the Supreme Court 39 times
The issue of abortion has long been a deeply divisive one in the US.
None of the Senate's 100 members have declared their opposition to Mr Roberts but some civil rights groups have expressed concern.
Some abortion rights campaigners are worried Mr Roberts may be sympathetic to an attempt to make abortions more difficult to obtain.
On the second day of his confirmation hearing, Mr Roberts came under intense criticism from Democrats, one of whom, Joe Biden, accused him of giving "misleading" answers.
"Go ahead and continue not to answer," Senator Biden said.
But he was in turn accused of interrupting Mr Roberts, who argued the senator would have had a whole answer had he allowed him to speak out.
Democrats also questioned Mr Roberts about his writings on civil rights dating back to his years as a lawyer in Ronald Reagan's administration.
Senator Edward M Kennedy accused him of showing a "narrow, cramped and mean-spirited view" in those writings, and of failing to show a full appreciation of discrimination.
But Mr Roberts denied having a problem with the 1965 Voting Rights Act, which guaranteed the right to vote to African American citizens.
"The constitutionality has been upheld, and I don't have any issue with that," he said.
He was also questioned on women's rights, the fight against terror and the balance of power between the branches of government.
The hearing by the Senate Judiciary Committee is due to be completed this week.
It is the panel's first Supreme Court confirmation for 11 years.