Research on the Courts of Appeals has been limited by the lack of a universe-level database covering the courts' 440,000 published opinions from 1892 to 2025. Using a multiple-step large language model approach, we create such a database, including metadata (e.g., the judges involved in each case), summary information (e.g., substantive and procedural issues raised, litigant types), and the decision's ideological direction (liberal or conservative). We validate our database against multiple sources, showing that our LLM output matches human coders 85-90\% on key summary variables and 80\% of the time on ideological direction. The new database will enable much more comprehensive analyses of the Courts of Appeals over time; as examples, we extend existing work on panel effects and ideological decision-making. More generally, the approach we take provides a pipeline for converting expert-written codebooks into machine-extractable facts, which has relevance for computational social science beyond judicial politics.

Which justices control the content of opinions of the U.S. Supreme Court? This is a central question in the study of judicial politics, yet both theoretical and empirical debates persist about whether judicial policy is most likely to fall at the location of the median justice, the median member of the majority coalition, or the opinion author. We propose a new empirical strategy to disentangle these competing theories of judicial influence. We use the Court's negative treatments of its own precedents to see which theory best predicts when the Court is likely to move away from an existing precedent (for example, by overruling or distinguishing a precedent). Specifically, we measure distance from a precedent-setting court to a precedent-treating court based on each theory (e.g. distance from the median justice in Roe to the median justice in Dobbs). The results show that the two median theories better predict negative treatments than theories of author influence; furthermore, the bulk of evidence places more weight on the locus of judicial power being at the median of the majority coalition. 

In this short paper I present a few practical tips for producing better published graphs. These include: making labels big enough to read; avoiding legends and labeling lines directly; using small multiple plots; and using different line types and shapes to draw distinctions. I illustrate these suggestions by improving all a few example published graphs. Finally, I provide replication code for implementing these suggestions in \emph{ggplot}.

The current reality of a conservative Supreme Court supermajority, formed in part due to Senate Republicans’ successful blockade of Merrick Garland in 2016, has raised the salience of proposals to reform the selection and retention institutions for justices to levels not seen since Franklin Roosevelt’s court packing proposals in 1937. While the passage of any reforms seems unlikely in the near future, the Court’s many high profile conservative rulings since 2020, including the overruling of Roe v. Wade, 410 U.S. 113 (1973), in Dobbs v. Jackson Women’s Health Organization, have only intensified scrutiny on the justices and the current practice of lifetime tenure.

In this Article, we contribute to the scholarly debate around court reform by employing computer simulations to project the future ideological composition of the Court and to evaluate the effect of potential reforms to the Court—as well as possible changes in norms surrounding appointment politics—on the ideology trajectory of the Court. In terms of reforms, we focus on the most widely discussed proposals: term limits and court packing. In terms of norms, we examine what would happen if the example of Garland in 2016—a Senate controlled by the opposite president of the party completing blockading any nominee—became commonplace.

We begin by producing a “baseline" prediction of the future ideological composition of the Court for the rest of the century. We show that the events of 2016—the Garland blockade and the election of Donald Trump—locked in place a solid conservative majority on the Court. Barring a string of unlikely events, this majority will persist for several decades into the middle of the 21st century. We also show that the Court is quite likely to remain polarized into two ideologically distinct blocs, with a near-empty center. As the conservative majority slowly dissipates, the median justice will probably swing regularly between the two blocs.

Next, we go beyond existing simulation approaches by developing a normative framework for tradeoffs implicit in different judicial selection and retention institutions. These tradeoffs arise because different degrees of judicial independence, as embodied by lower responsiveness to election results and longer tenures on the Court, create both costs and benefits to society. In particular, we simulate the introduction of both court packing and fixed term limits for justices. We show that the introduction of staggered term limits would prevent any long-run ideological bias in the composition of the Court. Compared to the status quo, term limits would have the effect of increasing the frequency of appointment conflict by making appointments more regular (e.g., once every two years); this regularity would also have the desirable effect of lowering the intensity of appointments, since every president would be guaranteed an equal number of appointments per term.

This paper provides a primer for estimating public opinion at the state level using the technique of Multilevel Regression and Postratification (MRP). We provide sample R code for creating estimates and give step-by-step instructions on setting up the data, running models, and collecting estimates.

Appellate courts with discretionary dockets have multiple ways to review lower courts.

We develop a formal model that evaluates the tradeoffs between “full review”—which

features full briefing, oral arguments, and signed opinions—versus “quick review,”

where a higher court can summarily reverse a lower court. We show that having the

option of costless summary reversal can increase compliance by lower courts, but also

distort their behavior compared to relying only on costly full review. When the higher

court is uncertain about the lower court’s preferences, the threat of summary reversal

can lead an aligned lower court to “pander” and issue the opposite disposition to that

preferred by the higher court. Access to summary reversal can therefore harm the

higher court in some circumstances. Our analysis provides a theoretical foundation for

growing concern over the U.S. Supreme Court’s “shadow docket”—of which summarily

reversals are a component—which has been empirically focused to date.

How have the politics of appointments transformed the United States Supreme Court? In this paper, we examine the past and future of the Supreme Court and the current conservative supermajority on the Court, with a particular focus on how this Court stands out from earlier courts. In particular, we trace the factors that allowed President Trump to reshape the Court with his three appointments in his first term. We also evaluate the importance of the conservative supermajority by connecting it to two important theories of collective decision making on the Court. We then show that the current court is a culmination of a “partisan sort” on the Court—a strict correlation between party and ideology—that began a few decades ago but did not crystalize until the 2020s. Finally, we summarize simulations showing that conservatives are likely to control the Court for several decades.

While Supreme Court nominations have become increasingly high-salience political events, we know little about their prioritization relative to other issues by core constituency groups. We examine how individual donors and the mass public prioritize nominations, as well as factors they believe presidents should consider when selecting judges. To do so, we constructed original questions for a survey of over 7,000 validated donors and a comparison general population sample. We find donors are substantially more likely to prioritize nominations than their general public co-partisans, particularly Republican donors. Further analysis suggests the prioritization gap is consistent with theories that donors are motivated to move policy towards the ideological extremes. Analyzing policy positions, the largest donor-public difference occurs for diversity in appointments, but for all positions we find smaller differences than for prioritization. Overall, the findings highlight donors' policy priorities may diverge from those of the public even more than policy positions do.

Kevin McMahon's A Supreme Court Unlike Any Other examines the extent to which the current Supreme Court—and its conservative supermajority—departs from earlier courts in the extent to which it suffers from a “democracy gap.” McMahon persuasively argues that the current Court is different for two reasons. First, most of the justices in the conservative majority were appointed by presidents who did not win the popular vote and/or were confirmed by senators who represented fewer voters than the senators who opposed them. Second, the homogenization of nominee experience and background has created a “judicial aristocracy” in which the justices are experientially far removed from the elected branches. One puzzle this account raises is why this democracy gap took so long to emerge, given the institutional design of the Court. But given the current polarized state of American politics, the same forces that brought us to the reality of the conservative supermajority are unlikely to abate for quite some time.

Despite the importance of every nomination to the Supreme Court, a unified theory that illuminates presidential selection of nominees across the modern political era remains elusive. We propose a new theory—the “characteristics approach”—that envisions nominees as bundles of characteristics, such as ideology, policy reliability, and attributes of diversity. We formalize the theory, which emphasizes the political returns to presidents from a nominee’s characteristics and the “costs” of finding and confirming such individuals, and derive explicit presidential demand functions for these charac- teristics. Using newly collected data on both nominees and short list candidates, we estimate these demand functions. They reveal some striking and under-appreciated regularities in appointment politics. In particular, the substantial increase in presidential interest in the Supreme Court’s policy output and the increased availability of potential justices with desired characteristics has led to significant changes in appointment politics and the composition of the Court.

Do senators respond to the preferences of their state's median voter or only to the preferences of their co-partisans? We develop a method for estimating state-level public opinion broken down by partisanship so that we can distinguish between general and partisan responsiveness. We use these estimates to study responsiveness in the context of Senate confirmation votes on Supreme Court nominees. We find that senators more heavily weight their partisan base when casting such roll call votes. Indeed, when their state median voter and party median voter disagree, senators strongly favor the latter. This has significant implications for the study of legislative responsiveness and the role of public opinion in shaping the members of the nation's highest court. The methodological approach we develop allows more nuanced analyses of public opinion and its effects, as well as more finely grained studies of legislative behavior and policy-making.

We study the relationship between state-level public opinion and the roll call votes of
senators on Supreme Court nominees. Applying recent advances in multilevel modeling, we use national polls on nine recent Supreme Court nominees to produce state-of-the-art estimates of public support for the confirmation of each nominee in all 50 states. We show that greater public support strongly increases the probability that a senator will vote to approve a nominee, even after controlling for standard predictors of roll call voting. We also find that the impact of opinion varies with context: it has a greater effect on opposition party senators, on ideologically opposed senators, and for generally weak nominees. These results establish a systematic and powerful link between constituency opinion and voting on Supreme Court nominees.

The Democrats' victory in the 2006 election has been compared to the Republicans' in 2004. But the Democrats actually did a lot better in terms of the vote. The Democrats received 54.8% of the average district vote for the two parties in 2006, whereas the Republicans only averaged 51.6% in 1994. The 2006 outcome for the Democrats is comparable to their typical vote shares as the majority party in the decades preceding the 1994 realignment. Nevertheless, the size of the Democrats' victory in the 2006 House elections has obscured the sizable structural disadvantages they faced heading into the elections. In this paper we document the advantages the Republicans had, examine how and to what extent the Democrats overcame it, and offer predictions as to whether the results of the 2006 election leveled the electoral playing field for 2008. Our calculations showed that the Democrats needed at least 52% of the vote to have an even chance of taking control of the House of Representatives.

Prior to the election we estimated the seats-votes curve for 2006 by constructing a model to predict the 2006 election from 2004, and then validating the method by applying it to previous elections (predicting 2004 from 2002, and so forth). We found that the Democrats in 2006 were always destined to receive fewer seats than their corresponding average vote share. They were able to gain control of the House by winning the largest average district vote by either party since 1990. Has the 2006 election removed the Republicans' structural advantages? While Republicans continue to win more close races, a preliminary analysis of the 2008 election suggests that the switch in incumbency advantage from the Republicans to the Democrats may nevertheless level the electoral playing field.