WASHINGTON — When the Supreme Court's term opens tomorrow, the justices will enter a new era in which new faces — including that of Chief Justice John Roberts — will help guide court consideration of familiar, high-profile issues.

Cases involving assisted suicide, abortion, the death penalty, religious liberty and states' rights appear on the docket.

By January, Roberts could make clear how his approach will affect some of the most controversial areas of the law. By June, when the term ends, it should be clear whether Roberts' leadership will achieve more agreement on the court than his former boss and mentor, the late William Rehnquist.

Roberts, 50, is the first new justice in more than 10 years and the first new chief in nearly 20. At some point this term, President Bush will fill the seat being vacated by Justice Sandra Day O'Connor, providing another new influence.

The job presents Roberts with immediate challenges.

For one, there are unanswered questions about O'Connor's departure. She said July 1 that she would be stepping down; Roberts was to replace her. But Bush shifted Roberts into the chief-justice opening after Rehnquist's death and O'Connor, at Bush's request, delayed her retirement.

O'Connor, 75, a moderate who often casts the critical fifth vote on the nine-member court, will hear cases and vote during closed-door sessions after oral arguments. Rulings take months to prepare, and if she leaves before they are done, the votes would not count.

"The court will be in an extremely unsettled and uncertain situation until Justice O'Connor's successor is confirmed and seated," Supreme Court historian David Garrow said. "No one — including the justices themselves — will know for sure whether the nine justices who hear a case will be the same nine who will decide it."

On Wednesday, the court hears a challenge to Oregon's assisted-suicide law. Oregon voters in 1994 approved the law that allows doctors to prescribe lethal doses of drugs to kill certain terminally ill patients.

The Bush administration claimed in 2001 that the law conflicts with the federal Controlled Substances Act. Former Attorney General John Ashcroft threatened doctors who participate in the program with the revocation of their licenses or criminal prosecution.

The case raises issues about the right to die and the nature of end-of-life care, and it evokes memories of the fight over Terri Schiavo, a brain-dead Florida woman whose mother and father fought to keep her feeding tube from being removed. Schiavo's husband fought to have the tube removed, saying his wife would not have wanted to live in such a diminished state.

But for the court, it is a question of federal versus state authority and the right of individuals to decide personal questions such as these for themselves. Roberts' approach suggests a clear direction in the case, and one he spoke publicly about the last time the high court dealt with the issue.

In 1997, the justices turned back a challenge to a Washington state law that prohibited assisted suicide, saying voters had a right to decide the issue for themselves.

Roberts, then a private attorney, said on PBS' "NewsHour" that he agreed with the ruling and expanded on what he thought was its chief virtue. "I think it's important not to have too narrow a view of protecting personal rights," Roberts said on the show.

"The right that was protected in the assisted-suicide case was the right of the people through their legislatures to articulate their own views on the policies that should apply in those cases of terminating life, and not to have the court interfering in those policy decisions. That's an important right."

If Roberts applies the same approach in the Oregon case, he easily could vote to uphold the law. If he leads the justices to a resounding opinion in that direction, it could make an early statement about the direction he has in mind for the court: one that emphasizes deference to democratic will, no matter the public opposition.

An abortion dispute in late November will test his commitment to Roe v. Wade and demonstrate how much leeway he thinks states should have to restrict abortion.

The case, from New Hampshire, involves a parental-notification requirement that does not provide an exception for health emergencies. The court has said health exceptions must accompany restrictions on abortion. But abortion opponents say the health exception should not always play the decisive role in determining whether a law is constitutional.

The case is not a test of Roe itself, and Roberts has said he considers the landmark ruling "settled precedent." But his vote and how he inspires the other justices to vote will be an indicator of how protected he believes the right to abortion must be.

The court also will take on the death penalty in a case that will determine when courts must consider claims of innocence raised long after the conviction and sentence of death-row inmates. The court has said late innocence claims don't always have to be heard but has not made clear when a new trial is warranted.

For Roberts, each case provides an opportunity to make his approach clear, and lead. "It will be his court," Garrow said. "And we'll know soon enough what that means."

Material from The Associated Press is included in this report.