THE SUPREME COURT regularly has to choose between issuing narrow rulings and issuing broader ones.
Suppose, for instance, that an alleged enemy combatant, who is also an American citizen, argues that he has a right to a hearing before he can be held as a prisoner by the United States. A minimalist court would be inclined to rule on the combatant's particular claim without saying a word about the president's general power to wage war on terror, and it would remain silent about the rights of foreigners.
Or suppose that an elderly cancer patient is challenging a state ban on physician-assisted suicide. A minimalist court would focus on the specific facts of the case and the law in question and refuse to say anything about whether the Constitution provides a more general right to privacy that might encompass a right to commit suicide.
Or imagine that a rejected white applicant is challenging an affirmative-action program at a particular medical school. A minimalist court might strike down the specific program for some narrow, perceived flaw in its structure without saying whether affirmative action is generally permissible.
Last week, when Chief Justice John G. Roberts Jr. delivered his first commencement address, at Georgetown University Law Center, he offered an original, substantive and unambiguous defense of narrow, minimalist rulings.
Roberts began by arguing in favor of unanimous or near-unanimous opinions, which, he said, serve the rule of law by ensuring that the court's message is not confused by its own internal divisions. He went on to suggest that such a consensus on the part of the justices would, almost by necessity, lead to narrow rulings, limited in most situations to the particular issue at hand.
"The broader the agreement among the justices, the more likely it is that the decision is on the narrowest possible ground," he said. After all, the nine justices have highly diverse views, and if they are able to join a single opinion, that opinion is likely to be narrow.
This, in the chief justice's view, is entirely desirable. "If it is not necessary to decide more to dispose of a case, in my view it is necessary not to decide more," he said.
Roberts made several approving references to Justice Felix Frankfurter, one of American history's great minimalist judges who consistently called for narrow rulings, especially on the issues that divide the nation most sharply. Writing more than 50 years ago, Frankfurter said that the court has an obligation "to avoid putting fetters upon the future by needless pronouncements today."
It was advice Frankfurter followed himself. In his opinion voting to strike down President Truman's 1952 seizure of the nation's steel mills, Frankfurter refused to say much about presidential power in general. He emphasized that "rigorous adherence to the narrow scope of the judicial function" is especially important when national security is at risk, notwithstanding the national "eagerness to settle -- preferably forever -- a specific problem on the basis of the broadest possible constitutional pronouncement."
Roberts referred, with unmistakable enthusiasm, to Frankfurter's suggestion that courts should focus on the concrete issue and "not embarrass the future too much."
What makes Roberts' argument noteworthy is that it takes a side in one of the deepest and most long-standing divisions in American jurisprudence -- a division that cuts across the standard ideological lines.
One strand of that jurisprudence, associated with justices Antonin Scalia and Hugo Black, prizes broad, ambitious rulings on the ground that they give the clearest signals to lower courts, potential litigants and the nation as a whole. Scalia has long attacked minimalism on the ground that a court that resolves "one case at a time" leaves far too much doubt. If the court focuses on particular facts, people won't know, for example, when affirmative-action programs are permissible, when government can interfere with private choices and what, exactly, the president may or may not do to protect the nation.
The competing strand, associated with Frankfurter and Justice Sandra Day O'Connor, prizes narrow rulings. O'Connor emphasized the need for humility, which would require the justices to acknowledge what they do not know and to leave many questions undecided.
In a period in which the court must answer many novel questions, there is a lot to be said for minimalism -- not least because it tries to avoid taking a stand on the most controversial questions and thus shows respect for people with reasonable competing views.
Indeed, narrow rulings help to promote a key goal of societies that are both diverse and free: to make agreement possible where agreement is necessary, while also making agreement unnecessary where agreement is not possible.
It remains to be seen whether the court as a whole might be willing and able to move in the direction of broader consensus and hence narrowness -- something Roberts can encourage in his role as chief justice.
If the court does move in that direction, its movement would have major consequences not only for privacy, free speech and the war on terror but for nearly every question that now divides both the court and the country.