Out of our Top 21, whom do you like best?

As a pre-eminent scholar of international law, Koh is a leading proponent of the notion that the United States can learn from the laws and judicial precedents of other countries. He has written and spoken about the role of "transnational jurisprudence"—a body of law that spans different countries and international courts—and has shown that since the founding, the decisions of foreign courts have influenced the development of American law. The far right attacked Koh's views on international law after Obama tapped him for the State Department legal post, even though they largely match the positions taken by a majority of the Supreme Court in cases like Roper v. Simmons, which abolished the death penalty for defendants who commit crimes as juveniles. In a friend-of-the-court brief filed in that case, Koh attached the juvenile death penalty for clashing with American interests. We've weighed in about the Koh bashing on Slate here and here. If appointed, Koh would become the first Asian-American to sit on the Supreme Court. (Disclosure: Emily Bazelon is a fellow at Yale Law School.)

Leigh Ingalls Saufley, 55,is the chief justice of the Maine Supreme Judicial Court and the first woman and youngest member of the court ever to be appointed chief justice. A graduate of the University of Maine-Orono and the University of Maine School of Law, Saufley logged 10 years of service in the state's Attorney General Office. As chief justice, Saufley has spearheaded efforts to bring mental health courts to Maine, giving offenders the option of accepting mental health treatment in lieu of going to jail. She also supported a Maine law that would restrict how much information the public receives about a jury, if a judge deems the information should be kept secret.

Notable cases: In 2007, she voted to approve a state statute requiring drivers involved in fatal car crashes to submit to blood tests for alcohol and other drugs, finding the privacy interests of drivers did not outweigh the state's need to determine whether they were using alcohol or other drugs prior to fatal crashes. In 1999, she voted with a unanimous court to dismiss a sexual abuse suit against the Jehovah's Witnesses, because to hold the church responsible would require delving into matters of redemption and forgiveness, ''an inquiry that would require secular investigation of matters that are almost entirely ecclesiastical in nature.'' In 1999, she also authored an opinion finding voucher funding of religious schools unconstitutional. If the president really wants a Supreme Court justice who is female, as an outsider with a dollop of David Souter's New England pragmatism, Saufley is an interesting choice.

Myron Thompson, 63, is a district judge in Alabama. President Carter chose him in 1980 at the age of 33 in an effort to put a black judge on Alabama's federal trial court. Thompson's opinions on voting rights and on who has standing to bring lawsuits are regularly invoked by other courts. He's also the judge who was undaunted by Alabama Chief Justice Roy Moore when Moore insisted on displaying a massive granite Ten Commandments monument in the courthouse. Thompson ruled that effort a violation of the constitutionally required separation between church and state. The religious right called for Thompson's impeachment, but the 11^th Circuit repeatedly upheld his rulings. Like the stone monument, Moore was finally removed from Alabama's court.

Elizabeth Warren, 60, has spent most of her career in academia but has a flair for public service. Though she's a tenured professor at Harvard, where she specializes in bankruptcy law, she's best known as the chairwoman of the Congressional Oversight Panel. At the COP, she polices the Troubled Assets Relief Program's $700 billion bank bailout with a populist zeal. Time  named Warren one of the 100 most influential people of 2009. Free-market advocates chastise Warren for her ardently pro-consumer politics. (Obama's proposed Consumer Financial Protection Agency, Warren's brainchild, particularly rankles the financial-services industry.) Though she has no experience on the bench, Warren's expertise in business law exceeds that of any justice on today's court.

"I'm convinced that no one grasps the true nature of our hard times better than Elizabeth Warren," Maxed Out director James Scurlock argued in The Big Money last year. Warren was raised in Oklahoma, the daughter of a janitor and a Sears employee. Unlike the vast majority of Supreme Court justices and potential nominees, she went to college and law school at non-Ivy League universities—the University of Houston and Rutgers Law. After co-authoring  The Two Income Trap: Why Middle-Class Mothers and Fathers Are Going Broke with her daughter in 2003, Warren has appeared several times on Dr. Phil and other national programs. Her experience on Dr. Phil, she has said, nudged her focus from ivory-tower scholarship to more direct forms of public service. An appointment to the high court would jibe with this trajectory.

Carter G. Phillips, 57, keeps a low public profile, but he's among the most accomplished Supreme Court lawyers under consideration. In March, the National Law Journal named Phillips one of the decade's 40 most influential lawyers. Phillips has argued more than 60 cases before the high court. Like Justice Stevens, Phillips earned his law degree from Northwestern University. Early in his career, Phillips clerked for Seventh Circuit appellate judge Robert Sprecher and Supreme Court Chief Justice Warren E. Burger. During his three years as assistant to the solicitor general, Phillips argued nine Supreme Court cases on behalf of the federal government. Today, he's a corporate lawyer and the managing partner at D.C. firm Sidley Austin LLP.

Notable Cases: In the Supreme Court case FCC vs. Fox Television Stations, et al., Phillips defended broadcasters' right to air the "F- and S-words" during live telecasts. Phillips argued that Americans have become more tolerant the F-word, especially when used fleetingly, and don't exclusively associate it with sexual obscenity. The high court decided 5-4 against the broadcasters last April. Phillips also wrote a widely cited friend-of-the-court brief in favor of affirmative action, siding with the University of Michigan law school in the 2003 Supreme Court case Grutter v. Bollinger. The university won that case 5-4.

Sidney Thomas, 56, is a relatively unknown federal judge out of Montana whose name has surfaced as a possible long-shot Obama nominee. He earned his bachelors from Montana State University and his law degree from the University of Montana before going into private practice at a firm in Billings, which could satisfy critics who want to see a more geographically and educationally diverse court. He taught law at Rocky Mountain College for over a decade until he was nominated by Bill Clinton to his current seat on the 9^th Circuit Court of Appeals in 1995. He was confirmed without controversy in 1996 and has served there ever since.

The 9th Circuit is typically considered liberal, but Thomas' peers say Thomas doesn't fit the stereotype. His former law partner Bernard "Bud" Longo, a conservative Republican, said that he "wouldn't class Sid Thomas with the Ninth Circuit," adding that he doesn't think Thomas is "as rabid as that bunch." There's not much in his record that stands out, with the exception of the 2006 civil rights case Nadarajah v. Gonzales. Ahi Nadarajah was part of an ethnic minority in Sri Lanka and repeatedly tortured before seeking asylum in the U.S. Upon arrival, he was imprisoned and detained for four years. Thomas ruled that government cannot authorize indefinite detention and that Nadarajah's imprisonment was illegal.

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