New York, NY –
It's a matter of timing, politics and, in some cases, luck.
President George W. Bush won two and lost two. Richard Nixon got four of his six picks through. Ronald Reagan nominated five and only lost one. And Jimmy Carter didn't get a chance to nominate any.
The Supreme Court's justices — once confirmed by the Senate — can serve for the rest of their lives, and their interpretations of the law generally last longer than any one president. So when justices' opinions oppose the views of a president, a well-crafted presidential legacy could be put at stake.
"Whenever you put a man on the Supreme Court, he ceases to be your friend," President Harry Truman once said.
Associate Justice David Souter has turned out to be more moderate than the conservative fans of then-President George H. W. Bush had anticipated. Harry Blackmun, a Nixon appointee, drifted to the left over his time on the bench, writing the majority opinion in 1973's Roe v. Wade decision, which protected the right to have an abortion. Over the course of their time on the court, Sandra Day O'Connor and Anthony Kennedy — both Reagan appointees — drifted to the left as well. This shift was balanced, however, by Reagan appointees Antonin Scalia and Chief Justice William Rehnquist — both staunch conservatives. More recently, President George W. Bush filled O'Connor's vacant seat with conservative Samuel Alito, in addition to placing John Roberts as Chief Justice. Appointed at 50, Roberts is relatively young. He could influence the court for decades.
Whomever is elected president this fall could be in line to replace at least two justices — the liberal-leaning John Paul Stevens and Ruth Bader Ginsburg. (They have made no announcements of any intention to retire, but Ginsburg, who has been treated for colon cancer in the past, would be 83 two terms from now, and Stevens, already the longest-serving member of the current court, would be 97.) But if confirmation hearings are up any time soon, the president will likely face a Democratic Congress, meaning extreme conservatives won't have a shot at the bench.
Judicial philosophies can be hard to quantify precisely, but one Web site, The Supreme Court Ideology Project, tracks the justices' positions over time, in comparison to their colleagues on the court. You'll find more links under the "Web resources" heading.