Sept. 27 (Bloomberg) -- The U.S. Supreme Court term that begins next week will test the willingness of Chief Justice John Roberts and Justice Samuel Alito to stand by previous high court rulings that bolstered affirmative action and abortion rights.

Roberts, 51, and Alito, 56, pledged after they were nominated last year that they would respect past decisions. Roberts warned in Senate testimony of a ``jolt to the legal system'' when the high court reverses itself.

Conservative groups nonetheless are asking the two new justices to help the court roll back precedents in both areas of law. The challenge is most direct in a fight over a federal ban on what opponents call ``partial birth'' abortion. The high court in 2000 struck down an almost identical Nebraska law.

How the court deals with the 2000 precedent will ``tell us a little bit about the soul of the Roberts court,'' said Steven R. Shapiro, the New York-based legal director of the American Civil Liberties Union, which opposes the abortion law. The case is set for argument Nov. 8.

The nine-month term also features two challenges to the use of race in assigning students to public schools. Those cases raise questions about a 2003 Supreme Court ruling that let universities consider race as an admissions factor.

Other top cases on the court's docket include fights over punitive damages and federal regulation of auto and power-plant emissions. The high court added nine new cases to its calendar yesterday, including fights affecting the insurance and waste- disposal industries.

Abortion Precedent

Some backers of the federal abortion law say the dispute presents an especially strong case for overturning a precedent. The 2000 ruling, Stenberg v. Carhart, said the Nebraska statute was too broad and should have allowed an exception to protect the mother's health.

The 5-4 ruling hasn't had much impact on American society or the law, unlike, for example, the 1966 Miranda ruling requiring police to tell suspects in custody of their right to remain silent, said Richard Garnett, a law professor at the University of Notre Dame in South Bend, Indiana.

``They could overrule it and still maintain plausibly that the role of judges is supposed to be humble and restrained and respectful of precedent,'' Garnett said.

The Bush administration, saying the federal and state laws define the banned procedure differently, contends the court can uphold the U.S. law without reversing Stenberg. At the same time, the government says the Stenberg ruling should be overturned if the court concludes the two laws can't be distinguished.

Major Statement

That would mark a major statement about the direction of the Roberts court, according to Susan Low Bloch, a law professor at Georgetown University in Washington.

``If they overturn a precedent that's only six years old in the abortion context, that's going to send out a lot of signals to a lot of people,'' Bloch said.

Stenberg was a 5-4 decision, with now-retired Justice Sandra Day O'Connor in the majority and the late Chief Justice William Rehnquist in dissent. To overturn it, both Roberts and Alito would have to join the majority, as would Justice Anthony Kennedy, a swing vote on abortion cases.

Kennedy co-wrote the 1992 Planned Parenthood v. Casey decision that reaffirmed abortion rights. The ruling relied heavily on ``stare decisis,'' the notion that justices should be slow to overturn settled precedents. Kennedy switched sides in Stenberg, complaining in dissent that the majority had gone too far and effectively barred any state regulation.

School Diversity

The education cases concern efforts by school districts in Seattle and Louisville, Kentucky, to promote racial diversity. A key precedent will be the court's 2003 Grutter v. Bollinger ruling, which let race be considered in university admissions.

Although the families challenging the Seattle and Louisville programs aren't seeking to revisit the 2003 ruling, Florida Governor Jeb Bush and others have filed friend-of-the-court briefs urging a reversal of the university decision.

The Grutter ruling ``swung open the doors to regimes that discriminate on the basis of race and ethnicity,'' argued Bush, a Republican.

The punitive damages dispute, which concerns a $79.5 million award to the widow of a former smoker, also may hinge on the approach of Roberts and Alito to precedent. Three justices -- Antonin Scalia, Clarence Thomas and Ruth Bader Ginsburg --have never accepted the court's decade-old ruling that imposed the first constitutional limits on awards.

Roberts and Alito

How much respect Roberts and Alito will accord to precedent isn't yet clear. At their Senate hearings, both nominees left themselves flexibility, pointing to the landmark 1954 Brown v. Board of Education school desegregation case as an instance in which the court properly abandoned a precedent.

One of the few hints about their views came in a campaign finance case resolved by the court in June. Justice Stephen Breyer's lead opinion invoked the stare decisis principle in refusing to let a state impose spending limits on candidates.

Alito opted not to join that section of Breyer's opinion, saying the issue wasn't directly presented in the case. Roberts, however, joined the passage, which said that ``departure from precedent is exceptional and requires special justification.''

Some court observers question whether Roberts would go along with a decision to overturn either the abortion or the affirmative action precedent.

``Given his institutional role as chief and given his new tenure on the court, I don't think he wants to send that kind of message of instability,'' said Shapiro, the ACLU lawyer. ``I don't think that without his support either of those two cases are really in play.''

To contact the reporter on this story: Greg Stohr in Washington at gstohr@bloomberg.net.

Last Updated: September 27, 2006 00:08 EDT