Much of the social science literature on judicial behavior has focused on the impact of ideology on how judges vote. For the most part, however, legal scholars have been reluctant to embrace empirical scholarship that fails to address the impact of legal constraints and the means by which judges reason their way to particular outcomes. This Article attempts to integrate and address the concerns of both audiences by way of an empirical examination of the Supreme Court's use of a particular interpretive technique--namely, the use of legislative history to determine the purpose and meaning of a statute. We analyzed every opinion in every Supreme Court statutory interpretation case from 1953 through 2006 that involved a frequently interpreted federal statute. We also collected original data on the characteristics of each statute, including its age, length, complexity, obscurity, and the number of times that it had been amended. We then used our data on these statutory characteristics--together with information on the ideological tilt of the Justices, the case outcomes, and the legislators who enacted the statute--in a logit regression analysis to determine the relative impact of each variable on the likelihood that a Justice would cite legislative history in a given opinion.
We find that the use of legislative history is driven by a combination of legal and ideological factors. On the whole, the legal variables have a significantly larger impact on the likelihood of legislative history usage than the ideological variables, but the impact of the ideological variables cannot be dismissed. Statutes that are longer or more complex increase the likelihood of legislative history usage, whereas frequent amendment of a statute decreases that likelihood. The age of the statute also matters, but its effect is neither linear nor monotonic: very new and very old statutes are more likely to elicit legislative history usage than statutes of intermediate age. Majority opinions are significantly more likely to cite legislative history than dissenting opinions, which in turn are more than twice as likely to cite legislative history as concurring opinions. Our findings also suggest that the use of legislative history by one Justice prompts other Justices to respond in kind with legislative history arguments of their own. We found no evidence, however, that the Court's adoption in Chevron v. Natural Resources Defense Council of the doctrine that reviewing courts should defer to reasonable agency interpretations affected the overall propensity of the Justices to cite legislative history.
With respect to the impact of ideological factors, liberal Justices are generally more likely than conservative Justices to cite legislative history. In addition, the Justices are more likely to consult legislative history when they are ideologically sympathetic to the purposes of the enacting Congress. At the same time, however, legislative history usage is not correlated with more ideological decision making. Although the decision to use legislative history is influenced by ideological factors, the actual use of legislative history does not make it more likely that a Justice will arrive at his or her preferred outcome. Moreover, contrary to what some scholars have suggested, we also found no evidence that Justice Scalia has persuaded other Justices to refrain from citing legislative history in their own opinions. Rather, the decline in the overall use of legislative history since the mid-1980s reflects a rightward shift in the ideological composition of the Court,
as liberal Justices who were inclined to cite legislative history have been replaced by conservative Justices who are not so inclined.
TABLE OF CONTENTS INTRODUCTION I. THE NORMATIVE DEBATE OVER THE USE OF LEGISLATIVE HISTORY II. THE STATE OF THE EMPIRICAL LITERATURE A. Trends in the Supreme Court's Usage of Legislative History over Time B. Reasons for the Court's Usage of Legislative History C. Legislative History Usage by the Lower Federal Courts D. Scholarly Assessment of the Impact of Justice Scalia on Legislative History Usage E. Two Overarching Weaknesses of the Judicial Behavior Literature III. THE DETERMINANTS OF JUDICIAL OPINION CONTENT: THEORIES AND HYPOTHESES A. The Inherent Difficulty of the Legal Question: The Guidance-Seeking Hypothesis B. The Purpose and Function of the Opinion: The Precedent-Crafting Hypothesis C. The Effect of Precedent: The Jurisprudential-Regime Hypothesis D. The Dynamics of Disagreement: The Outcome-Justifying and Tit-for-Tat Hypotheses E. The Impact of Ideology: Sincere Versus Instrumental Ideological Behavior 1. The Sincere Ideological Behavior Hypothesis 2. The Instrumental Use Hypothesis 3. The Ideological Alignment Hypothesis F. The Possibility of Intellectual Leadership: The "Scalia Effect" Hypothesis IV. METHODOLOGY AND DATA COLLECTION A. Data on the Opinions B. Data on Characteristics of the Statutes C. Data on Ideological Factors V. DESCRIPTIVE STATISTICS A. Characteristics of the Statutes B. Which Statutes Generate the Most Legislative History Usage? C. Which Justices Use Legislative History the Most? D. Is Legislative History Usage on the Decline? VI. EMPIRICAL ANALYSIS AND RESULTS A. Description of the Regression Model B. The Results of the Regression 1. Formal and Legal Variables 2. Ideological Variables 3. The Impact of Justice Scalia C. Evaluation of the Relative Impact of Legal and Ideological Factors D. Is Legislative History Usage Motivated by Disagreement Among the Justices? 1. The Outcome-Justifying Hypothesis: The Impact of Disagreement on the Merits on Legislative History Usage 2. The Tit-for-Tat Hypothesis: The Impact of Legislative History Usage on Legislative History Usage CONCLUSION INTRODUCTION
There are two principal, and conflicting, views as to why judges turn to legislative history when interpreting statutes. One view---often associated with Justice Scalia, but also consistent with a wealth of judicial behavior literature that depicts judges as ideological and strategic decision makers--is that they do so cynically, as a means of securing for themselves the interpretive flexibility they need to arrive at the substantive outcomes they prefer. (1) A different and long-popular view, which in recent years has been most visibly championed by Justice Breyer, is that judges should and do cite legislative history for the innocuous reason that it is a useful aid to interpreting statutes that lack clear meaning. (2)
Both views rest upon descriptive assertions about judicial behavior that have, for the most part, gone untested. But it is not simply the motivations behind legislative history usage that remain shrouded in mystery. More generally, relatively little is known empirically about the determinants of judicial opinion content and the reasons for which judges employ particular materials and techniques in the course of reaching their decisions. (3) To what extent does law matter, and to what extent does ideology matter? This Article tackles these questions by way of an empirical analysis of the reasons for which Supreme Court Justices have resorted to legislative history over the last fifty years. We engage in the most comprehensive examination of the Court's use of legislative history to date, in light of both the variety of explanations that we consider and the range of data that we analyze. In the course of investigating legislative history usage, we also study the formal and linguistic characteristics of a broad range of federal statutes. The results of our efforts to measure various substantive aspects of these statutes in an objective manner may be of interest in their own right to many scholars.
Our conclusion is that the Justices use legislative history for both legal and ideological reasons, but the legal reasons are predominant. On the one hand, the Justices appear to resort to legislative history partly for reasons having to do with the form and content of the statutes themselves. In particular, they are more likely to consult legislative history when faced with statutes of a certain age, level of complexity, or degree of amendedness. On the other hand, the propensity of Justices to cite legislative history is significantly correlated with the ideology of the Justices themselves: liberal Justices are more likely than conservative Justices to use it. In addition, the fact that a Justice is of the same ideological bent as the legislators who enacted the statute increases the likelihood that he or she will turn to legislative history. At the same time, however, the fact that a liberal Justice cites legislative history in a particular opinion does not render it more likely that the opinion in question will arrive at a liberal outcome.
Finally, we reject the oft-expressed hypothesis that Justice Scalia's vocal criticism of legislative history helps to explain the overall decline in legislative history usage since the Burger Court. (4) The decline is more likely attributable to the overall rightward shift in the composition of the Court, for which no single Justice can be assigned either credit or blame. Liberal Justices who were inherently predisposed to use legislative history have, on the whole, been replaced by conservative Justices who are not. Controlling for such factors as the ideology of each Justice, we found no evidence that Justice Scalia has influenced the legislative history usage of other members of the Court.
THE NORMATIVE DEBATE OVER THE USE OF LEGISLATIVE HISTORY
For much of the twentieth century, the Supreme Court embraced the use of legislative history in statutory interpretation cases with growing enthusiasm. From the 1930s to the 1980s, legislative history appeared in the Court's opinions with increasing frequency, reaching a high of 450 citations in the 1974 term. (5) It was during this time that the Court came to adopt what is now the conventional view that "proper...