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Legal scholarship highlight: Activism and the Roberts Court

Lee Epstein is the Provost Professor of Law and Political Science and the Rader Family Trustee Chair in Law at the University of Southern California.  Andrew D. Martin is Vice Dean and Professor of Law at Washington University in St. Louis.

Is the Roberts Court especially activist or, depending on your preference, especially lacking in judicial self-restraint? If we define judicial self-restraint as a reluctance to declare legislative action unconstitutional and confine the analysis to the 1969–2009 Terms,* the answer – as we explain in an article in the Emory Law Journal – is no. The Justices of the Roberts Court, like their immediate predecessors, are neither uniform activists nor committed restraintists. Rather, the Justices’ votes to strike (and uphold) statutes seem to reflect their political preferences toward the policy content of the law, and not an underlying preference for restraint (or activism).

In a nutshell, liberal Justices tend to invalidate conservative laws and conservative Justices, liberal laws. This holds regardless of whether we examine all the Justices’ votes simultaneously or each Justice individually.

Figure 1 below tells the paper’s primary story. The left-hand column shows the fraction of votes to strike in all cases in which the Court considered the constitutionality of a conservative law. The right panel shows the same fraction for liberal laws. Following other studies, we measure the ideological content of the law on the basis of the ideological direction of the Court’s decision.

Figure 1. Voting to Invalidate a Federal, State, or Local Law in All Cases Reviewing the Constitutionality of a Law, 1969–2009 Terms

A pattern seems to emerge. The conservative Justices (e.g., Alito, Rehnquist, Roberts, and Thomas) appear at the top of the left panel of the figure, meaning they exercise “judicial restraint” when reviewing conservative laws; liberals (e.g., Black, Ginsburg, Brennan, and Souter), on the other hand, appear at the top of the right panel revealing a similar level of “restraint” over liberal laws.

Various statistical analyses confirm this visual inspection. No matter how we measure ideology and what other factors we take into account, the basic finding remains. The statistical analysis shows that the probability of invalidating a liberal law decreases from .52 to an improbable .20 as we move from the most conservative to most liberal Justices (all else being equal). As for conservative laws, the probability declines even more dramatically, from a .81 invalidation prediction for the most liberal Justices to .31 for the extreme conservatives.  [Does this suggest that the liberal Justices are more “strike happy” (i.e., more activist) than the conservatives? Perhaps.  But the comparison assumes an equal number of opportunities to invalidate conservative and liberal laws—an assumption the data do not meet. Between the 1969 and 2009 Terms, the Court reviewed the constitutionality of conservative laws nearly three times as often as liberal laws.]

With the notable exception of Kennedy, the Justices of the Roberts Court (with sufficient votes for analysis) fit this basic pattern. As Table 1 shows, the four conservatives (Thomas, Scalia, Alito, and Roberts) are all highly unlikely to invalidate conservative laws. The range in the predicted probabilities of invalidating is narrow, from 0.02 for Alito for 0.27 for Scalia. The four most liberal Justices, on the other hand, are significantly more likely to invalidate conservative (relative to liberal) laws. The model predicts that Ginsburg votes to strike in seven out of every ten cases involving a conservative law but only in about two out of ten involving a liberal law. Even for Breyer, the most likely to uphold right-leaning legislation, the ideological direction of the law is a statistically significant predictor of his vote. More generally, looking down the third column of the table, from the most conservative to the most liberal Justice, we see that the predicted probability of invalidating a liberal law declines in a near monotonic fashion.

Table 1. Predicted Probability of Invalidating Legislative Action for Recent Justices (with More than 50 Votes in our Dataset)

JusticeOrdered from Most Conservative to Most Liberal

(N of Votes)


Predicted Probability of Striking a Conservative Law [95% Confidence Interval] Predicted Probability of Striking a Liberal Law [95% Confidence Interval]
Thomas (247) 0.20[0.13, 0.28] 0.62[0.47, 0.76]
Scalia (362) 0.27[0.21, 0.35] 0.61[0.47, 0.72]
Alito (59) 0.02[0.00-0.09] 0.54[0.10-0.94]
Roberts (65) 0.17[0.06-0.37] 0.46[0.16-0.79]
Kennedy (323) —– —–
Souter (241) 0.71[0.60, 0.80] 0.22[0.11, 0.35]
Breyer (200) 0.53[0.41, 0.65] 0.16[0.07, 0.29]
Ginsburg (206) 0.67[0.54, 0.78] 0.17[0.08, 0.30]
Stevens (636) 0.72[0.66, 0.77] 0.28[0.20, 0.38]


What should we make of Justice Kennedy? Judged on the basis of whether he was in the majority when the Court struck down legislative action, Kennedy is the most aggressive of the Roberts Court Justices.  When the Court invalidated a federal, state, or local law between the 2005–2009 Terms, Kennedy was in the majority 94% of the time. Only Roberts (at 72%) came close. But, unlike the other Roberts Court Justices, there is no underlying ideological pattern in Kennedy’s votes; as a statistical matter, he is equally as likely to sustain (or invalidate) conservative as liberal laws.

If, however, we consider only laws reviewed by the Court since the start of the Roberts Court years, even Kennedy’s ideology shows in his votes—he too is now substantially more likely to strike liberal laws than conservative laws.

Along these lines, Figure 2 is illuminating. There we compare the predicted probability of invalidating laws for Justices Ginsburg, Kennedy, and Alito since the 2005 Term. All else being equal, Kennedy isn’t as extreme as either Ginsburg or Alito, but the difference in his willingness to invalidate liberal versus conservative law is substantial: 38% versus 16%.

Figure 2. Predicted Probability of Invalidating a Law for Justices Ginsburg, Kennedy, and Alito, 2005–2009 Terms


Ours will certainly not be the last word on judicial self-restraint during the Roberts years. The data we have amassed cover only the first five Terms of the current era. As Justices come and go, the Court may move further to the right, turn sharply to the left, or perhaps steer a more moderate course. Whether the underlying patterns we have uncovered will dissipate remains another story. At least since 1969, there is a clear ideological structure to the Court’s review of the constitutionality of federal, state, and local laws—the Roberts Court Justices not excepted.


*This caveat is important because Epstein and Landes, analyzing data for a far longer time span (1937– 2009 Terms) but studying federal laws only, reach a somewhat different conclusion.  They find that the majority of Justices appointed before the early 1950s were reluctant to strike down laws regardless of whether the law accorded with their ideological values. But for Justices appointed since 1952, Epstein & Landes’s findings parallel ours: the vast majority were opportunistic restraintists (activists), willing to uphold laws that were consistent with their policy preferences and strike those that were not.


Recommended Citation: Lee Epstein and Andrew Martin, Legal scholarship highlight: Activism and the Roberts Court, SCOTUSblog (Nov. 12, 2012, 11:24 AM),