Liberals do have more to celebrate this term than in the recent past, from the same-sex marriage and Obamacare decisions, to a major housing discrimination case, to a surprising win for minority plaintiffs in a voting rights lawsuit. In all of those cases, Kennedy was in the majority, and all but one — Obamacare — were decided 5-4.
But there were some victories for conservatives as well. The court blocked a key environmental rule on mercury pollution. It upheld Oklahoma's lethal injection method. And it rejected an attempt to put a Texas voter identification law on hold even after a federal court found that the legislature intended to discriminate against minority voters. Kennedy was in the majority in these rulings.
Indeed, there were only a handful of important cases this term in which Kennedy was on the losing side of a 5-4 split, such as the Williams-Yulee case, in which Chief Justice John G. Roberts Jr. sided with the four liberals against Kennedy and three conservatives to uphold Florida's ban on judicial candidates personally soliciting campaign contributions.
Looked at over the long run, Kennedy's influence seems even greater. Think of the Supreme Court's 5-4 decision in the 2010 Citizens United case striking down the ban on corporate spending in elections, which has opened the floodgates to "super PACs" and big money in politics. Or consider the court's 5-4 decision in the 2013 Shelby County case, which eviscerated a key provision of the Voting Rights Act. Kennedy was in the majority in each instance.
His power won't lessen any time soon. This week the court said it would review a case that could kill public sector unions, overturning long-standing precedent. Kennedy will probably cast the crucial fifth vote. And, no doubt, the court's upcoming decision on how far states can go in restricting abortion will depend on Kennedy's view of what constitutes an "undue burden" on a woman's right to choose.
It is no surprise, as professor Nan Hunter of Georgetown remarked, that Supreme Court advocates often write their briefs for an audience of one: Kennedy.
How does the court's swing voter choose sides? The evidence suggests that Kennedy goes with his gut and personal sense of morality rather than a well-thought-out and consistent jurisprudential theory.
Consider, for example, the contrast between the court's decision last term in an affirmative action case called Schuette and its decision last week in the Obergefell case finding a constitutional right to same-sex marriage.
In Schuette, Kennedy wrote that Michigan voters could pass a ballot measure banning the use of affirmative action in college admissions. Arguing in favor of judicial restraint, he said the decision was best left to the democratic process. Kennedy wrote: "Were the court to rule that the question addressed by Michigan voters is too sensitive or complex to be within the grasp of the electorate … or that these matters are so arcane that the electorate's power must be limited because the people cannot prudently exercise that power even after a full debate, that holding would be an unprecedented restriction on the exercise of a fundamental right held not just by one person but by all in common."
Yet when it came to same-sex marriage, Kennedy was just as content to take the question away from the voters. He wrote for a different 5-4 majority in Obergefell: "It is of no moment whether advocates of same-sex marriage now enjoy or lack momentum in the democratic process. The issue before the court here is the legal question whether the Constitution protects the right of same-sex couples to marry."
How to reconcile the two cases? The answer seems to lie in Kennedy's psychology. He is skeptical of race-based preferences but not of gay rights. When to trust the voters? When they are likely to agree with Kennedy.
Driven by feeling over theory, Kennedy also has the frustrating habit of taking nondefinitive positions as he makes up his mind. He's skeptical of racial preferences, but not so skeptical that he's willing to completely jettison affirmative action. And so the law remains uncertain. He's troubled by partisan gerrymandering, but is reluctant to police legislatures. And so the law remains uncertain.
It's crazy to have major social and public policy questions depend so much on Kennedy's whim, not to say what he had for breakfast. But it could be worse. As much as liberals would love to see Kennedy retire and be replaced by another Elena Kagan or Sonia Sotomayor, depending on the next election, we could get another Samuel A. Alito Jr. or Antonin Scalia. Then we'll be pining for the days when Kennedy ruled America.
Richard L. Hasen is a professor of law and political science at UC Irvine and the author of the forthcoming book, "Plutocrats United: Campaign Money, the Supreme Court, and the Distortion of American Elections."