Ronald Dworkin, a professor at New York University and the University of Oxford who died this week, was one of the most important legal philosophers of the last 100 years. He may well head the list.

He made countless enduring contributions to philosophy and legal theory. Among his greatest is a distinctive answer to a longstanding question: Do judges find law, or do they make it? His answer is a huge improvement over the crude alternatives that dominate public debates.

Consider a question about which people fiercely disagree: Does the U.S. Constitution require states to recognize same-sex marriages? In answering that question, judges have to deal with many precedents. For example, the Supreme Court has ruled that states can’t criminalize sexual acts between people of the same sex. The court has also forbidden states from banning racial intermarriages. At the same time, the court allows states to forbid polygamous marriages.

In resolving the same-sex marriage dispute, how can judges deal with such precedents? Here Dworkin introduced an arresting metaphor. Suppose that you are a participant in writing a chain novel. Others have written earlier chapters. Now it’s your turn. How shall you proceed?

Dworkin’s answer is that you have to engage in an act of interpretation. You can’t disregard what has come before. If your predecessors have started to write a romance, you can’t suddenly turn it into a work of science fiction without doing violence to what they have done. You owe a duty of fidelity to their work.

But your task is not mechanical. You have to fit the existing materials, and you have to justify them, by writing a new chapter that makes the emerging novel, taken as a whole, the best it can be.

Dworkin thinks that judging is a lot like that. Precedents are like the existing chapters, and a new case is an opportunity to produce a fresh one. Judges can’t just make the law up. But at least in hard cases, they can’t merely “follow the law,” because there isn’t anything to “follow.” What they have to do is produce a principle that both fits and justifies the existing legal materials. This is Dworkin’s conception of law as integrity.

Under Dworkin’s approach, it would be lawless for a judge to rule that the Constitution gives states complete freedom to define marriage. Such a ruling would fail to fit existing law. And because the court has allowed bans on polygamous marriages, it would be similarly lawless for a judge to rule that the Constitution allows people to marry anyone they like.

But judges could consider some competing principles. Maybe the best one is this: “Unless they are discriminating on the basis of race, the matter of marriage is within the control of states, so long as they are acting in accordance with traditional understandings of the institution of marriage.”

Or maybe the best one is this: “States may restrict the institution of marriage to two people, but because of the central place of the institution of marriage in our society, they may not forbid gay men and lesbians from having access to that institution.”

Dworkin’s deepest claim is not about outcomes, but about constitutional method. He contends that judges, whether conservative or liberal, need to ask which principle is best, in the sense that it fits with the fabric of existing law and makes good sense out of it. When conservatives and liberals disagree, those are the legitimate grounds of disagreement. What else could judges possibly be disagreeing about?

There are some tempting answers. One response, associated with Supreme Court Justices Antonin Scalia and Clarence Thomas, is originalist. Perhaps specific constitutional questions should be resolved by asking: What was the original public meaning of the Constitution’s terms at the time the document was ratified? Dworkin doesn’t think that when the Constitution was ratified, it was understood to set out specific answers to specific questions, and hence he believes that Scalia’s version of originalism is self-defeating, because it is inconsistent with the original understanding.

But Dworkin has an even more fundamental objection: Does originalism fit and justify our own constitutional practices, including, for example, the ban on school segregation, the ban on sex discrimination and the broad principle of freedom of expression? Dworkin believes that it fails to fit our practices, and that it doesn’t make good sense of them. In his view, originalists must also help write America’s continuing chain novel, and their own chapter does the project no service.

I had my own disagreements with Dworkin. In person and in print, we had numerous debates about constitutional law; I believe that he would give an excessively large role to federal judges in American society. But I learned, as did everyone who encountered him, that he had one of the finest and most probing minds on the planet, and that if you were lucky enough to lose an argument to him (winning was out of the question), your own understanding would be immeasurably improved. He was not only a giant but also a good and gracious man.

On the Supreme Court and the Constitution, let’s give him the last word: “We have an institution that calls some issues from the battleground of power politics to the forum of principle. It holds out the promise that the deepest, most fundamental conflicts between individual and society will once, someplace, finally, become questions of justice. I do not call that religion or prophesy. I call it law.” 

By Cass R. Sunstein

Cass R. Sunstein, the Felix Frankfurter professor of law at Harvard University, is a Bloomberg View columnist. He is the co-author of “Nudge” and author of “Simpler: The Future of Government,” to be published in April. The opinions expressed are his own. ― Ed.

(Bloomberg)