WASHINGTON - One of the few things conservatives and liberals agree on when it comes to Sonia Sotomayor is that her views on abortion rights are a mystery - one that must be solved before she can be confirmed as a Supreme Court justice.

Unlike many liberal groups that swiftly backed Sotomayor's nomination, abortion-rights groups are withholding support until she answers questions on the court's 1973 legalization decision and the principles behind it.

NARAL Pro Choice America praised her experience and background but stopped well short of endorsing her.

"We look forward to learning more about Judge Sotomayor's views on the right to privacy and the landmark Roe v. Wade decision as the Senate's hearing process moves forward," the group's president, Nancy Keenan, said.

Neither abortion-rights advocates nor foes take any comfort from the abortion-related cases on which Sotomayor has ruled as a federal judge - none of which were decided on the principles or precedents underlying Roe.

"I don't think anybody can draw a conclusion," said Charmaine Yoest, president of Americans United for Life, which opposes abortion rights.

On the opposite side, Vicki Saporta, president of the National Abortion Federation, said: "We don't have enough information to take a position at this time. We're waiting to learn more about Judge Sotomayor's views on the constitutional right to privacy, including the right to choose."

The White House spokesman edged carefully around the issue yesterday in an animated question-and-answer session in which reporters pressed to know whether President Obama had ascertained Sotomayor's views before nominating her.

Robert Gibbs said the two discussed Sotomayor's "views on unenumerated rights in the Constitution and the theory of settled law" - buzz-phrases for backers of the 1973 decision.

In Roe, the court recognized a right to privacy even thought it is not spelled out in the Constitution.

Obama was "very comfortable with her interpretation of the Constitution being similar to that of his," Gibbs said.

Gibbs said neither Obama nor his aides asked Sotomayor specifically about her view of Roe or privacy rights.

The court has recently been closely divided on abortion questions. In the latest such ruling - of major concern to abortion-rights supporters - the court upheld a nationwide ban on a procedure its opponents call partial-birth abortion, a decision both sides said could pave the way for further restrictions.

It was the first abortion ruling in which the court did not require an exception to preserve a woman's health.

Sotomayor's decisions give little clue about her views on the subject, although she has issued two rulings on unrelated issues that favored opponents of abortion rights.

In 2002, she dismissed a challenge by an abortion-rights group to a policy of denying federal funding to organizations that provide or promote abortions.

Two years later, she ruled that abortion-rights protesters who had unsuccessfully tried to sue Hartford, Conn., police officers for using excessive force against them should, in fact, get to go to court.

Neither case turned on the key questions of reproductive rights, privacy, or Roe itself.

"Sure we're concerned, and I think most people who are on our side . . . are concerned, but we're happy to take a wait-and-see attitude," said Doug Laube of Physicians for Reproductive Rights.

"It gives me some consolation that they're concerned," said Yoest of Americans United for Life.