Split decisions: good for democracy? Photographer: Chip Somodevilla/Getty Images
Split decisions: good for democracy? Photographer: Chip Somodevilla/Getty Images

(This is the second of two essays. Read Part 1.)

In many of its most important cases, the modern U.S. Supreme Court has divided 5-4. By a single vote, the court guaranteed the presidency to George W. Bush, upheld the Affordable Care Act and affirmative action in university admissions, and ruled that government cannot prevent corporations from spending money in political campaigns. As the court prepares to issue this year’s most significant decisions, it’s a good bet that several of them will show 5-4 divisions as well. Is this a problem?

Many people think so. In 2006, Chief Justice John Roberts, referring to the court’s separate opinions and public disagreements, said it was ripe for a “refocus on functioning as an institution, because if it doesn’t it’s going to lose its credibility and legitimacy.” He emphasized the importance of promoting “the notion that we are a Court -- not simply an assemblage of individual justices.” (Since then, Roberts has not succeeded in reducing divisions within the court. On his watch, there has been no statistically significant decrease in the number of 5-4 splits.)

There are three reasons to object to the court’s continuing divisions. The first involves the chief justice’s principal concerns: credibility and legitimacy. The meaning of the U.S. Constitution often seems to depend on a single vote, and conservative and liberal justices predictably disagree. Can we really separate legal judgments from political judgments or continue to believe that our system follows the rule of law?

The second objection involves stability. When the court decides by a margin of 5-4, its ruling does not seem firm and fixed. With a single new appointment or a shift in just one person’s view, the law could lurch in a new direction. True, the court does not like to overrule its own precedents, but it has done so well more than 200 times, and a 5-4 decision is not likely to receive the highest level of respect.

The third and most subtle objection points to the fact that if the court is unanimous, it is probably ruling narrowly and cautiously -- which is often a good thing. In contrast, five justices might well be acting too boldly, because they haven't had to worry about attracting the support of the other four. Roberts has pressed this particular point, urging that the “broader the agreement among the justices, the more likely it is a decision on the narrowest possible grounds."

But there are strong counterarguments. Many constitutional cases are genuinely hard to decide. A 5-4 split attests to the existence of competing arguments, which are made visible to the public. In some cases, it is a mistake, even a form of deception, to insist that political and legal judgments can be rigidly separated. It is true that when the court divides 5-4, the public might be especially willing to question its decision. But in a democracy, that kind of questioning is desirable, and it is potentially productive for the future course of the law.

To be sure, 5-4 decisions might be especially vulnerable to being overruled, but that’s not necessarily bad, either. If the court is almost evenly divided, its decision might well deserve more scrutiny. A unanimous or near-unanimous decision, in contrast, deserves particular deference.

Minimalism certainly has its virtues. Narrow, unambitious rulings reduce the risk that the court will overreach. But sometimes nonminimalist rulings have their own virtues; even when the court is divided, such decisions can settle an assortment of issues, and they might even vindicate fundamental rights.

In its great 1964 decision establishing the principle of "one person, one vote," for example, the court was not unanimous, but its ambitious ruling has been widely applauded. Of course, the court did not need to be divided in order to receive that applause, but if the justices had sought an internal consensus, they would not have been able to settle on the broad principle.

We should not lament 5-4 rulings. They signal that, with respect to the meaning of the Constitution, reasonable people sometimes disagree -- and that course corrections are possible over time.

To contact the writer of this article: Cass R. Sunstein at csunstei@law.harvard.edu.

To contact the editor responsible for this article: Mary Duenwald at mduenwald@bloomberg.net.