Senate Judiciary Committee Chairman Joseph R. Biden Jr. (D-Del.) said yesterday that Supreme Court nominee David H. Souter should provide "some rather specific answers" to questions about abortion and other controversial issues at confirmation hearings scheduled to begin Thursday.

But Sen. Arlen Specter (R-Pa.), a moderate Republican on the committee, urged colleagues to use restraint in attempting to pin down Souter on specific issues and said no single issue such as abortion should dominate the selection of a Supreme Court justice.

In back-to-back speeches on the Senate floor, Biden and Specter dramatized divisions within the Senate over how far members should go in questioning the New Hampshire federal judge about his views on politically volatile issues that are pending -- or are expected to come up -- before the high court.

While Biden has the upper hand as chairman of the committee and its presiding officer for the confirmation hearings, debate over the Senate's role in confirming judges is far from over and is expected to influence the tone of the Souter proceedings.

Meanwhile, opposition to Souter's nomination from women's rights groups mounted yesterday as the National Organization for Women (NOW) said it "strongly opposes" Souter's nomination and the Women's Legal Defense Fund said it will oppose his nomination if he does not "articulate his support for women's constitutional and legal rights."

"Instead of viewing the U.S. Constitution as a living document brilliantly designed to grow with a changing society, Souter seeks the 'original intent' of the framers of the 18th century -- a time when all blacks were slaves and women were the property of their husband," said NOW President Molly Yard.

But the conservative Concerned Women for America endorsed Souter, and Beverly LaHaye, its founder and president, charged that Biden's "intent to grill Judge Souter on his political and personal opinions is an attempt to politicize and pervert America's judicial system."

Planned Parenthood released a poll showing that Americans by a margin of 76 to 20 percent want the Senate to ask Souter about his personal views on issues such as privacy, abortion, church-state relations and civil liberties. Planned Parenthood President Faye Wattleton said her organization is not currently taking a position on Souter but said he should not be confirmed if he does not answer questions on key subjects.

Biden did not say what he would do if Souter declined to answer questions as fully as he wants. But, in his first public comment on the extent to which senators should question Souter about abortion and other specific issues, Biden asserted that the burden of proof is on a nominee to convince senators, just as senators must convince their constituents that they are "the right persons for the job."

Biden called Souter's nomination "the most important business to come before the Senate this year" and said Souter's influence on the court would far outlast most of Congress's other current preoccupations, including the Persian Gulf crisis.

Moreover, he said there are "more blank spaces than answers" in Souter's record and expressed concern about some of Souter's statements on gender discrimination, judicial activism and other issues.

"At this fateful moment in our history, we have a right to know -- and a duty to discover -- precisely what David Hackett Souter thinks about the great constitutional questions of our time," Biden said.

Questions addressed to nominees over the years have set precedents that suggest "there is nothing wrong in putting to Judge Souter some rather specific questions about constitutional issues -- including religion, speech, civil rights and abortion -- and expecting some rather specific answers," Biden said.

Biden said he is not looking for "promises" but rather "how he {Souter} views these questions at this time, how he approaches them as a matter of constitutional reasoning."

Specter said abortion should not dominate the Souter debate to the exclusion of many other issues, ranging from war powers in the Persian Gulf to the death penalty, and said that "retention of an independent judiciary requires restraint by the public and senators in asking for the nominee's ultimate views" on an issue.

Specter said there is no absolute standard for determining what questions a judicial nominee should be expected to answer.

"If any valid generalization can be gleaned from the record, at least as I see it, it is that nominees for the Supreme Court answer as many questions as they feel necessary to win confirmation," he said.

Staff writer Maralee Schwartz contributed to this report.