One notable difference between early empirical legal scholarship and the more recent sophisticated contributions to the literature is scholars' goal of identifying cause and effect relationships.  Professors Cox and Miles's recent study of judicial decisionmaking provides a terrific example of this new-generation work.  The authors investigate whether personal attributes such as ideology, race, or gender cause judges to favor (or disfavor) plaintiffs' claims under section 2 of the Voting Rights Act.  The study is a valuable contribution to the emerging body of empirical scholarship exploring causal relationships, and to the work on judicial decisionmaking and voting rights litigation in particular.

Causal inference, as opposed to making claims about mere correlations, is, of course, an ambitious undertaking.  Investigators must spend time and energy exploring the underlying relationship between and among the variables of interest in order to identify possible bias and confounding in their data and, importantly, to address these perceived problems with appropriate conceptual and statistical methods.  If bias and confounding exist but are not—or cannot be—remedied, scholars must exercise humility in reporting empirical results:  They may point to interesting correlations in the data, but causal claims would be completely unjustified.

In this Response, we use Professors Cox and Miles's study of judicial decisionmaking to explore what is at stake when legal scholars present empirical findings without fully investigating the structural relationships of their data, or without explicitly stating the assumptions they make in order to draw causal inferences.  We do not intend merely to identify the limitations of Cox and Miles's work (and by implication, those of many other empirical studies published in the extant legal literature); rather, we plan to introduce a new methodology that is intuitive, easy to use, and, most importantly, allows scholars to systematically assess problems of bias and confounding.  This methodology—known as causal directed acyclic graphs—will help empirical researchers identify true cause and effect relationships when they exist, and at the same time posit statistical models with appropriate controls, in order to better justify causal claims.  While this methodology has become popular in a number of disciplines—including statistics, biostatistics, epidemiology, and computer science—and is widely believed to be a valuable tool for empirical research, it has yet to appear in the empirical law literature.  Accordingly, our goal is to offer a brief introduction of the method and to initiate discussion as to its worth in empirical legal studies.

A.J. Bellia and Brad Clark have performed a valuable service for other scholars interested in foreign relations law and federal jurisdiction by collecting and illuminating—with their usual care and insight—the historical practice of both English and early American courts with respect to the law of nations.  Their recent Article, The Federal Common Law of Nations, demonstrates that, while American courts have not generally treated customary international law (CIL) as supreme federal law, they have applied such law where necessary to vindicate the "perfect rights" of foreign nations.  In so doing, American courts have protected the prerogatives of the political branches to "recognize foreign nations, conduct foreign relations, and decide momentous questions of war and peace."  Although Professors Bellia and Clark disavow any attempt "to settle all questions of how customary international law interacts with the federal system," they do suggest that their approach represents a middle ground between proponents of the "modern position" that CIL simply is federal common law and critics of that position, who insist that CIL may be applied by American courts only where it is incorporated into the domestic legal system through an affirmative act by the political branches.

This response makes three points.  First, I quibble with the historical account offered by Professors Bellia and Clark on two minor, yet at least somewhat significant, grounds:  The debate over reception of the common law at the federal Constitutional Convention shows greater early skepticism about judge-made common law than Bellia and Clark suggest; also, the jurisdictional provisions of Article III covering cases implicating foreign affairs were not intended fully to centralize power over such cases in federal courts because they left concurrent jurisdiction in the state courts.  Second, I question the extent to which the Founding Era history is directly relevant to contemporary debates about how to treat CIL.  Finally, I contend that what does the real work in the Bellia and Clark approach is simply constitutionally-grounded concerns about the separation of powers in foreign affairs cases, not anything about CIL per se.  Their position thus reduces to the largely uncontroversial claim that federal courts may make federal common law to protect these constitutionally-grounded federal interests, and they may sometimes draw the content of federal common law from international law.

We would like to thank Rick Swedloff and Peter Huang for taking the time to comment on our Essay, and it is a pleasure to engage in a dialogue with them about hedonic adaptation.  In every instance, however, their critiques miss the mark.  Swedloff and Huang have mischaracterized many of our key arguments, and the remainder of the significant points made in their responses were anticipated and answered in our Essay.

Let us begin with a one paragraph summary of our Essay to clarify what we have claimed.  Civil procedure scholars have spent decades analyzing the circumstances under which lawsuits settle.  We argue that the settlement models created by those scholars have omitted a relevant factor:  plaintiffs' psychological adaptation to their ailments.  Because people adapt to certain injuries—i.e., their happiness or subjective well-being increases with time, even if the injury is permanent—the sum they will accept in settlement should decrease as time passes, all else being equal.  That is the sum and substance of our claim.

Adam Kolber's thoughtful essay contends that variations in the subjective experience of punishment warrant a more nuanced manner by which courts mete out sentences for violations of criminal law.  Failure to take subjective experience into consideration, Kolber argues, violates not only notions of retributive justice, but also consequentialist arguments grounded in theories about how we can best deter crime.

This Response considers Kolber's consequentialist arguments in light of the neoclassical economic understanding of deterrence.  According to the standard economic understanding of criminal law, individuals are deterred from committing crimes when they are made to feel "costs" equivalent to the harm they cause society, modified by the probability that they will be punished.  When the "costs" of engaging in criminal conduct outweigh the net benefits of such conduct, the criminal refrains from committing that crime.  Apart from reputation costs and moral qualms, the government-mandated punishment that the criminal defendant receives upon conviction is a significant portion of the costs that she must weigh against the perceived benefits of completing a given crime.

In his provocative essay, The Subjective Experience of Punishment, Professor Adam Kolber addresses an underappreciated problem in criminal law theory:  What is the relevance of the criminal defendant's subjective experience of punishment to the justifiability of that punishment?  As Kolber explains, punishment theorists have neglected to analyze carefully whether the harsh conditions of punishment should be understood objectively (e.g., as a deprivation of liberty) or subjectively (e.g., as the physical or emotional distress that the particular offender suffers).  Retributivists, he points out, have said relatively little about the issue, and also have much greater difficulty than consequentialists reconciling their views with his stance, which I will call the "subjectivist" view.  In this Response, I suggest that Kolber understates the conceptual and normative difficulties with the subjectivist view, and is mistaken in believing that only a subjectivist version of retributivism is defensible.

In Hedonic Adaptation and the Settlement of Civil Lawsuits, Professors John Bronsteen, Christopher Buccafusco, and Jonathan Masur note an unexplored aspect of protracted lawsuits:  During prolonged litigation tort victims can adapt emotionally to even permanent injuries, and therefore are more likely to settle—and for less—than if their lawsuits proceeded faster.  This Response demonstrates that this is a facile application of hedonic adaptation with the following three points.  First, people care about more than happiness:  Tort victims may sue to seek justice or revenge; emotions in tort litigation can be cultural evaluations; and people are often motivated by identity and meaning.  Also, if plaintiffs fear losing litigation options, they are less likely to settle—and for more—than if their lawsuits proceeded faster.  Second, adaptation can be slow and remain incomplete after many years.  Third, fostering emotional adaptation by lengthy tort litigation raises ethical and normative questions.