Fill Souter's shoes with a genial persuader

Filling the shoes of Supreme Court Justice David Souter, who announced his retirement Friday, will not be easy. I clerked for Justice Souter in the 1999-2000 term and left that job with a respect for the judge matched only by my affection for the man.

It's been said that President Obama's appointment won't be a transformative one. That's true in one sense. Justice Souter generally voted with the moderate to liberal justices, and his replacement will almost surely do so also. In terms of net votes, the liberal/conservative balance will not change. But the vacancy offers Mr. Obama an early opportunity to make a lasting mark on the country.

That's because he can do more than appoint a reliably liberal jurist – which wouldn't greatly affect the court's rulings. He can appoint a jurist with that rare ability to persuade her conservative colleagues – which emphatically would affect the court's rulings.

Such a quality will be vital in the years ahead. Think how many crucial issues – from the 2000 election to gun control to eminent domain – have been decided by 5-to-4 rulings in recent years. Obama's nominee may well serve on the bench for the next 30 years. In just the next few years, her ability to build a coalition, or lack thereof, could decide the answers to such high-stakes questions as abortion, same-sex marriage, race-based affirmative action, and privacy.

Thus, the community-organizer president needs to pick a coalition-builder justice.

As my pronoun choice suggests, I think Obama should pick a woman. The sexes plainly have different experiences, and a woman will bring to the Supreme Court a life history and set of understandings a man would not. That the current court consists of nine former federal court of appeals judges has been thought problematic. It is surely as important to have women on the court as it is to have people with experience in legislatures or executive office, especially when well-qualified female candidates abound.

As Obama considers how to maximize the impact of his selection, he should bear in mind that justices exert influence in two ways.

The first is through their writing. A good literary style can go a long way toward winning popular acclaim. If it is coupled with obvious intellectual power and a judicial philosophy that can be summed up in sound bites and zingers, so much the better. A brilliant justice with a knack for the mot juste will see his memorable phrases repeated by lower court judges and law professors. He will gain plenty of acolytes outside the Supreme Court.

Oliver Wendell Holmes, who coined the phrase "clear and present danger," is a good example of this sort of influence; so too is Robert Jackson, who warned "We can afford no liberties with liberty itself." Both were very smart; both are frequently quoted. On the current court, one of the smartest justices, and probably the best stylist, is Antonin Scalia, who turns a phrase with a pleasingly wicked point.

Pleasing to the outside reader, anyway. The weakness of the brilliant justices, or many of them, is that they tend to lag in their ability to wield the second kind of influence: influence over their colleagues. They are good at writing opinions, but less good at building a majority. The reason: People who agree with a position love to hear justices who reject it skewered with a rapier epigram. But people who disagree are not likely to be moved, and that goes double for the justices themselves. No one enjoys being on the receiving end of a laugh line.

And so Scalia is also notable as a justice who has been unable to get majority support for many of his positions, even on a court with seven Republican appointees. Felix Frankfurter, another titanic intellect, met a similar fate. For years he explained patiently to the other justices just how stupid they were for not seeing things his way. Astonishingly, they never came around.

One need not always choose between the two kinds of influence. William Brennan, who had some pretty good lines, was also a master at forging consensus. He knew, as Justice Souter once put it, how to count to five. But if an appointing president has to lean in one direction or the other, a coalition-builder is better than a genius who alienates potential allies. On the Supreme Court, stylistic facility will not win votes. Sheer intellect will not do it either, nor a sound-bite judicial philosophy. Scalia's originalism doesn't win even his vote sometimes – you will search his affirmative action opinions in vain for any reference to the original understanding of the equal protection clause.

Given the circumstances Obama faces, his need to appoint someone who excels at the second kind of influence is great. Replacing Souter will not increase the liberal bloc. Other liberals – Ginsburg and Stevens – are widely considered the justices most likely to step down next. For the near future, then, victories can be won only by getting the vote of one of the five more conservative justices, most probably Anthony Kennedy.

For that task, it will matter very little whether Obama's nominee is brilliant, or whether her opinions draw chuckles in law school faculty lounges. Her influence will lie not in the voice that speaks to the public but rather in the lower tones that carry no farther than the marble halls of One First Street.

Kermit Roosevelt, who clerked for Supreme Court Justice David Souter, teaches law at the University of Pennsylvania's law school.