Describing the Justices of the Supreme Court as "liberals" and "conservatives" has become so standard--and the left-right division on the Court is considered so entrenched--that any deviation from that pattern is treated with surprise. Attentive Court watchers know that the Justices are not just politicians in robes, deciding each case on a purely ideological basis. Yet the increasingly influential empirical legal studies literature assumes just that--that a left-right ideological dimension fully describes the Supreme Court. We show that there is a second, more legally-focused dimension of judicial decision making. A continuum between legalism and pragmatism also divides the Justices in ways that cut against ideological preferences. The second dimension is systematic and significant, occurring in multiple legal areas and in consistent patterns. Seen in this way, the Justices (and their decisions) can be understood in more complex terms, not just as ideological flag bearers, but as jurists who regularly have to choose between legal methodology and outcome preferences. In two dimensions, different patterns of coalitions emerge: in the second dimension, it is the Chief Justice and Justice Sotomayor, not Justice Kennedy, who sit at the median of the Court and decide the balance of power.
TABLE OF CONTENTS
INTRODUCTION I. JUDICIAL DECISION MAKING: ONE DIMENSION OR TWO? A. The Standard Assumption of a One-Dimensional Supreme Court B. Scaling the Roberts Court in One and Two Dimensions II. THE SECOND-DIMENSION CASES IN THE ROBERTS COURT A. Identifying Second-Dimension Cases B. A Theory of the Second Dimension: Pragmatism Versus Legalism CONCLUSION INTRODUCTION
Observers of the Supreme Court have become so accustomed to viewing it as a political body that they often seem surprised when the Justices deviate from their typical coalitions. For example, when the Court decided Williams v. Illinois, a case applying the Confrontation Clause to expert testimony involving crime lab reports, (1) the New York Times highlighted the "odd-bedfellows coalition of justices" constituting the majority. (2) Similarly, when the Court held in Maryland v. King that the Fourth Amendment permitted police to take DNA swabs as part of routine booking procedures, (3) the Times pointed out the "alignment of justices that scrambled the usual ideological alliances." (4)
Williams and King, however, did not feature merely unusual voting alignments; they featured the same unusual alignment. In both cases, Justice Breyer joined with four conservatives, Chief Justice Roberts and Justices Kennedy, Thomas, and Alito, to form a majority; Justice Scalia joined three of the liberals, Justices Ginsburg, Sotomayor, and Kagan, in dissent. (5) The same divide has also appeared in several other cases. In Adoptive Couple v. Baby Girl, the same majority held that the Indian Child Welfare Act (ICWA) did not govern adoptions of Native American children when the Native American parent had never had custody prior to the adoption. (6) Maracich v. Spears, a case involving the Driver's Privacy Protection Act of 1994, divided along the same lines, (7) but with a twist: the majority that opposed constitutional privacy rights in King supported statutory privacy rights in Maracich, (8) while the dissenters supported constitutional privacy rights but not statutory ones. (9)
When such "unusual" coalitions keep recurring, especially in cases involving diverse legal issues and policy implications, it is appropriate to question how unusual they really are. Although most "unusual" alignments do not coincide exactly with the divide that occurred in Williams, King, Adoptive Couple, and Maracich, we find that many divisions on the Court adhere to a common structure. A few prior commentators have noted such recurring alignments in particular doctrinal areas, such as in cases involving the Confrontation Clause, (10) the right to a jury trial, (11) punitive damages, (12) and search and seizure questions. (13) We show that such alignments transcend particular substantive areas of law. These patterns of coalitions are not idiosyncratic but rather are evidence of a second dimension in Supreme Court decision making.
Patterns of coalitions that divide across party lines are only one sign of a second dimension of Supreme Court decision making. When cases divide into the so-called unusual alignments, which are not really so unusual, the rationales that the Justices give also follow a discernible pattern. The Roberts, Breyer, Kennedy, and Alito group often points to pragmatic reasons for its decisions, such as considering individualized fairness, the practical ramifications of its determinations, and the broad policy goals of lawmakers. (14) They tend to favor balancing tests and broad holdings, rather than rigid rules that apply regardless of circumstance. (15) In contrast, the Scalia, Ginsburg, Sotomayor, and Kagan wing of the Court typically relies on more legalistic determinations, prioritizing development of clear rules, closely tied to the plain meaning of legal sources, adherence to positive law, and consistency in application, without exceptions for individual cases. (16) When the most natural interpretation of legal sources conflicts with the most desirable result in a particular case, the legalists tend to favor the former while the pragmatists favor the latter. (17) The division reflects the trade-off between rule of law values and individuated fairness. Justice Thomas consistently sided with the legalists during the early years of the Roberts Court but has occasionally defected from the legalist coalition in recent Terms, although sometimes on grounds that are unrelated to the legalismpragmatism divide. (18) Justice Sotomayor could be considered the swing vote in the second dimension, a position also occupied by her predecessor, Justice Souter. (19) What emerges from this understanding is a second dimension characterized by division based primarily on legal methodology.
Although contemporary discourse about the Court often views it as one-dimensional, this was not always the case; early research in judicial politics often viewed the Court as multidimensional. (20) More recently, many scholars have again challenged the dominant conception of the Court as one-dimensional. (21) This Article is the first to establish empirically the existence, nature, and effect of a second, methodologically based dimension of decision making on the Supreme Court. Most scholars agree that a simple left-right, one-dimensional spectrum cannot account for the full considerations of the nation's top judges, but many empirical studies of the judiciary ignore this reality. (22) The one-dimensional assumption persists because (1) it is convenient--it makes measuring judicial preferences easy; (2) even though most scholars agree the assumption is inapt, due to simple path dependence, it goes unquestioned because others have done the same; and (3) it has never been clear how to tell if a second dimension exists. However, the existence of a legally based dimension that shapes Supreme Court rulings should come as little surprise to most Court observers. Although it is common now for both popular and scholarly accounts of the Supreme Court to depict the Justices as occupying only a left-right, one-dimensional spectrum, (23) scholars have long recognized that such a characterization does not come close to capturing the full considerations of the nation's top judges. (24) It is well understood that legal considerations are also significant determinants of judicial decision making. (25) More specifically, the division between legalism and pragmatism is a well-established distinction. (26) Nevertheless, almost all empirical studies of the judiciary ignore this reality and assume a simple, one-dimensional model of judicial decision making that captures only ideological division. Ignoring what we show to be the significant effect of legal methodology on judicial decision making leads to unreliable empirical conclusions and a distorted view of judicial behavior and the judicial role.
This work in no way denies the contribution of the existing empirical literature that has established the significance of the left-right "first dimension" on the Court. That literature represents an important field that has shown the influence of ideology on judicial behavior, from nominations (27) and choice of cases, (28) through to final decisions, (29) opinion writing, (30) and coalition formation. (31) But hiding in plain sight in all of those studies is an inherent limitation of the extent to which they can provide a nuanced understanding of judicial behavior without factoring in a legal dimension of judicial decision making. We find that, indeed, a large number of cases split between the liberal and conservative blocs, but many do not.
We also do not deny that Justices sometimes allow their preferences for particular outcomes to override their methodological commitments. Some of the first-dimension divides may arise when legalists disagree about the best interpretation of a legal text or pragmatists disagree about which consequences are most desirable. At other times, outcome preferences may simply overwhelm legal principle.
Furthermore, the differences between legalist and pragmatic judges are a matter of degree rather than kind; most judges value adherence to clear rules, and most judges seek to avoid patently unjust results. For this reason, the second-dimension divisions that we observe typically arise in close cases in which there is some ambiguity in the legal sources and a tension between the most natural interpretation of those sources and the most sensible policy. In our view, the common characterization of such divisions as "unusual" stems from a highly simplistic conception of judging as a purely political enterprise. Simply acknowledging the role of interpretive methodology explains a large...