With reports of ill health and old age plaguing the justices of the Supreme Court, it is likely that the next president will have a significant impact on the composition of the country's most powerful judiciary.
Experts say that up to three new justices, including the chief justice, may be appointed in the next four years, but cautioned that the number of appointments likely depends on which candidate wins tomorrow's election.
Justices are more likely to retire if they believe the elected president will appoint a judge who will interpret the Constitution in a similar fashion to their own.
The makeup of the Court is particularly important this election, as the justices are likely to take on a number of contentious issues in the next four years, including criminal sentencing, partial-birth abortion and congressional redistricting, according to Penn Law professor Nathaniel Persily.
The Court has gone 10 years without a change in membership, the longest period without an alteration since the early 19th century. Currently, conservative justices hold a loose 5-4 majority, though Justice Sandra Day O'Connor frequently provides a key swing vote.
O'Connor recovered from breast cancer 16 years ago. She has expressed interest in retiring, according to Political Science Department Chairman Rogers Smith.
The first woman to serve on the Court, O'Connor often writes narrower, concurring opinions on issues including the separation of church and state, civil rights and abortion.
For example, although she criticized the constitutional foundation of the landmark Roe v. Wade case of 1973, which established that a woman's choice to have an abortion was protected under constitutional privacy rights, she did not join justices who wanted it totally overturned.
Currently, six justices support Roe, including O'Connor and John Paul Stevens, who is also considering retirement.
The 80-year-old chief justice, William Rehnquist, is one of the dissenters to the polarizing opinion.
A strong supporter of states' rights, Rehnquist interprets the Constitution narrowly, using a legal philosophy known as judicial restraint.
He was recently released from the hospital following throat surgery related to thyroid cancer. Having served on the Court since 1972, he is expected to be the first to retire.
But health problems have troubled Stevens as well, who is the Court's oldest justice.
Treated for prostate cancer over a decade ago, 84-year-old Stevens votes unpredictably on a case-by-case basis. He has championed abortion rights and opposed the death penalty, but he also dissented when the Court ruled in 1989 that flag-burning is protected by the First Amendment.
Likely successors will depend on the winner of tomorrow's presidential election.
President George W. Bush has cited conservative justices Clarence Thomas and Antonin Scalia as models for future appointees, while Democratic presidential nominee John Kerry has said he will appoint judges committed to civil and abortion rights.
Scalia's strict interpretation of the Constitution has led him to argue that a St. Paul, Minn., ban on hate crimes violated freedom of speech and that abortion is a political issue that should be decided by elected branches of the government.
Bush, who is anti-abortion, has said he will not use that issue as a litmus test for appointing judges.
Depending on the outcome of the election, several individuals have already been named as possible successors.
"There are some lower federal court justices, such as Harvie Wilkinson and Michael McConnell, whom the Republicans favor. Democrats are more likely to go for legal academics like Cass Sunstein of" the University of Chicago, Smith said. "Some have speculated that either Bush or Kerry might appoint Arlen Specter, and that's plausible -- he'd be easy to confirm."
Specter is currently a U.S. senator from Pennsylvania and is seeking to be elected to his fifth term tomorrow. Specter is a Republican but advocates abortion rights.
However, the controversy surrounding Supreme Court composition seems unlikely to be a deciding factor for most voters.
"Many voters are concerned about the direction the Supreme Court might go with a new president, but these concerns generally only express preferences that have already led them to decide who to vote for," Smith said.
However, a president's legacy can be determined by the justices appointed during his term. Justices often have a lasting impact and can dictate the course of law over several decades.
The appointments "could make all the difference in the world," Persily said, noting the close division of the court on many important issues.
