Not so suddenly, there’s an elderly quartet at the Supreme Court. Ruth Bader Ginsburg just turned eighty-one, and she’s followed closely in age by Antonin Scalia, seventy-eight; Anthony Kennedy, seventy-seven; and Stephen Breyer, seventy-five. None of these Justices has signalled a desire to leave the Court anytime soon, but time catches up with everyone.

If President Obama has another chance to fill another vacancy (or more) on the Court, he will be in a very different position than he was when he nominated Sonia Sotomayor and Elena Kagan in the first and second years of his Presidency. Presidents generally pick Justices who were appointed to the federal appellate courts by Presidents of their own party; given enough time, they can pick federal judges whom they appointed themselves. Now, unlike in 2009 and 2010, Obama has his own farm team of appellate judges. According to Obama Administration insiders (and knowledgeable outsiders), here is a preliminary list of possibilities.

Sri Srinivasan, age forty-seven, D.C. Circuit. As I’ve noted before, Srinivasan is the front-runner. Like Sotomayor, Srinivasan has a great (and marketable) American story. The child of immigrants from India, Srinivasan grew up in Lawrence, Kansas, earned a J.D./M.B.A. from Stanford, and clerked for a pair of Republican judges, J. Harvie Wilkinson III and Sandra Day O’Connor. As Obama’s deputy solicitor general, he argued twenty-five cases before the high court and then won confirmation to the D.C. Circuit last year by a vote of 97–0. Even in the malignant political atmosphere of the contemporary Senate, that margin might make him a safe pick for the Supreme Court. Would Obama nominate a man to replace Ginsburg, and reduce the number of women on the Court to two? Making history with the first Indian-American Justice might tempt him.

Paul Watford, age forty-six, Ninth Circuit. Watford, a former law clerk to Alex Kozinski (the well-regarded Republican chief judge of the Ninth Circuit) and to Ginsburg herself, served as a federal prosecutor and corporate lawyer in Los Angeles before his appointment to the Ninth Circuit, in 2012. Again, there is the potential problem of naming a man to replace Ginsburg (if she leaves), but choosing Watford, who is African-American and a Ginsburg clerk, might make the decision easier.

David Barron, age forty-six, nominated to the First Circuit. Barron served as acting assistant attorney general during the first two years of the Obama Administration and is now a professor at Harvard Law School. His clerkships were with Stephen Reinhardt (a liberal favorite on the Ninth Circuit) and Justice John Paul Stevens; he has many fans in the White House, though the appointment of a white male would offer few political benefits. Barron’s nomination to the First Circuit has been approved by the Judiciary Committee on a party-line vote, and he has apparently been promised a vote in the full Senate before the mid-term elections. The invocation of the nuclear option—confirmation via a simple majority rather than the three-fifths vote formerly required to overcome a filibuster—should guarantee his appointment, which is obligatory if he is to be a Supreme Court nominee down the line.

The next two prospective nominees are more likely if Republicans take control of the Senate in the 2014 elections. To the extent that it’s possible to determine, they have a more moderate political profile than those listed above, and so, perhaps, a better chance of being confirmed.

Jane Kelly, age forty-nine, Eighth Circuit. A 1991 graduate of Harvard Law School, i.e., Obama’s class, Kelly has an unusual and welcome background for a Supreme Court Justice. She’s a career public defender who has practiced almost entirely in Iowa. Most important for confirmation purposes, she has an enthusiastic fan in Charles Grassley, the Iowa Republican who may well be chairman of the Judiciary Committee if the G.O.P. takes control. Last year, she was confirmed 96–0 for her seat on the Eighth Circuit.

Patricia Ann Millett, age fifty, D.C. Circuit. A former lawyer in the Solicitor General’s office with thirty-two Supreme Court arguments to her credit, Millett was the least controversial of the three judges recently confirmed, thanks to the nuclear option, for the D.C. Circuit. The wife of a Navy reservist, Millett has been an advocate for military families, which is a confirmation-friendly activity.

Most of the names on this list would probably carry over to a Democratic President elected in 2016—say, Hillary Clinton. If a Republican wins, there is an alternative farm team already in place, which certainly includes Paul Clement, the former solicitor general under President George W. Bush; Brett Kavanaugh, a judge on the D.C. Circuit (and a principal author of the Starr report); and Diane Sykes, a judge on the Seventh Circuit.

Politicians like Kamala Harris, the attorney general of California, and Amy Klobuchar, the senior senator from Minnesota, are often mentioned for Supreme Court vacancies—and the Court could use some occupational diversity. Mike Lee, the forty-two-year-old senator from Utah, who clerked for Samuel Alito on the Supreme Court, and Lindsey Graham, the South Carolina senator, are Republican alternatives in the same vein. Still, the nods tend to go to judges or law professors (or, like Scalia, Ginsburg, and Breyer, those who are both). That’s one reason why circuit-court appointments and confirmations are so important. The circuits are the fields where Supreme Court Justices grow.

Above: Patricia Ann Millett, a judge on the D.C. Circuit. Photograph by Bill Clark/CQ Roll Call/Getty.