A. Levels of Mobilization

We begin our analysis by examining levels of mobilization. For each nominee, we first calculated the number of unique groups mentioned by the newspapers as participating in the confirmation process. Figure 1A displays these data; note that, to make the graph more readable, the horizontal axis displays each nomination separately and is thus not perfectly scaled to time.Footnote ¹³ The filled circles denote unsuccessful nominees, while the open circles denote confirmed nominees.

Figure 1.

A, Interest group mobilization over time; points display the number of unique groups mobilizing for each nominee; filled circles denote unsuccessful nominees, while the open circles denote confirmed nominees. Vertical dashed lines at the Burger (1969) and Bork (1987) nominations demarcate what we contend are three distinct eras. B, Interest group mobilization, support and opposition; dotted line depicts mobilization by groups opposed to the nominee, while the solid line depicts mobilization by groups supporting the nominee.

Figure 1A reveals a clear change over time. The number of groups that mobilized in the 29 nominations from Charles Evans Hughes to Warren Burger (1930–69) was typically low; indeed, nearly half (13) of these nominations witnessed no mobilization, with the mean level at 3.1 groups in this period. The nomination of Clement Haynsworth (1969) marked a shift, with higher levels of mobilization subsequent to his controversial nomination. From 1969 to 1986, the year in which William Rehnquist was promoted to chief justice and Antonin Scalia was appointed, the mean number of groups that mobilized was 9.8. The nomination of Robert Bork occurred in 1987; figure 1A shows that the level of mobilization during the Bork nomination was—and remains—unprecedented, with more than 80 groups taking part. Since the Bork nomination, the levels of mobilization have fluctuated, with the nominations of Clarence Thomas, John Roberts, and Samuel Alito triggering a large number of groups. The mean number of groups in the 1987 to 2017 period was 32.4 (28.3 if Bork is excluded).Footnote ¹⁴

Mobilization, of course, occurs on both sides of a nomination fight. Figure 1B disaggregates the data into the number of groups who mobilize in support of the nominee and the number who mobilize in opposition. The graph shows that until very recently, mobilization against a nominee was typically larger than mobilization in support of a nominee. Indeed, the latter is a relatively recent phenomenon and hardly existed until the Bork nomination. Since then, supportive mobilization has become more common; moreover, the ratio of supportive to opposing mobilization has virtually equalized in the past few nominations. This equalization may reflect a growing sophistication of the president in organizing what are virtually political campaigns on behalf of a Supreme Court nominee.Footnote ¹⁵

B. Who Participates: One-Shotters, Repeat Players, and the Changing Nature of the Groups

While figures 1 and A-4 establish the increase in aggregate mobilization, it is also of interest whether the types of groups that participate in Supreme Court nominations have changed. Given the broader changes in nomination politics over this time, we would expect the composition of groups to change as well.

First, our data reveal an important pattern in the overall distribution of mobilization by different interest groups. For each group in our data set, we calculated the number of nominations in which they participated. Figure 2 depicts the distribution of these rates of participation—the horizontal axis depicts the number of nominations they participated in, while the vertical axis depicts the aggregate number of groups for each level of participation. The graph shows that the majority of groups (236, to be exact) are “one-shotters”—they mobilize in one and only one nomination. Conversely, there are a smaller number of “repeat players”—groups who have mobilized across multiple nominations.Footnote ¹⁶

Figure 2.

Frequency of mobilization across interest groups. The horizontal axis depicts the number of nominations participated in, while the vertical axis depicts the aggregate number of groups for each level of participation.

The repeat player groups are of greater interest for our longitudinal analysis. Table 1 shows who these groups are. The top panel depicts the 10 most frequently appearing groups (in descending order) that mobilized across our entire time period, while the next three panels break down the data into the three time periods indicated in figure 1: Hughes (1930) to Burger (1969), Haynsworth (1969) to Scalia (1986), and Bork (1987) to Gorsuch (2017). The number of nominations in which each group mobilized in the respective time period are shown in final column of table 1. Looking first at the entire period, table 1 reveals that the most frequent participants are liberal groups such as the NAACP, the National Abortion Rights Action League (NARAL), and People for the American Way, as well as the AFL-CIO federation of unions.Footnote ¹⁷

Table 1.

The 10 Most Active Groups, First across the Entire Time Period, Then in Each Era

Note.—Groups appear in descending order of total mobilization; final column depicts the number of nominees the groups mobilized for. The nature of mobilized groups has shifted dramatically, from industrial unions, core civil rights groups, and old right groups to public sector unions, the Christian right, lifestyle activists, new-style liberal groups, and staged pro-administration front groups.

Perhaps more illuminating, however, is the transformation in the types of groups seen in the bottom three panels of table 1. The three most frequently appearing groups in the early period were the American Bar Association; the AFL-CIO, a core industrial union; and the Liberty Lobby, a conservative anticommunistic bulwark of what we label the “old right.” In the middle period, extremely prominent groups were the Leadership Conference on Civil Rights (LCCR), the NAACP, and the National Organization of Women (NOW). Finally, the third period sees the rise of the aforementioned liberal groups that focus on social issues and identity politics.

How might we characterize interest groups more systematically? Scholars have attempted to organize the interest group system using a number of different typologies, each presenting its own advantages and difficulties. Most divide the interest group universe on the basis of the policy areas in which groups operate or the constituencies they represent (see, e.g., Walker Reference Walker1991; Baumgartner et al. Reference Baumgartner, Berry, Hojnacki, Kimball and Leech2009). We began with a fine-grained classification scheme that would allow us to better discriminate between the types of groups who participate in Supreme Court nominations. Categories in this scheme include, for example, groups involved in environmental and health politics, as well as abortion and gay rights groups. (The complete taxonomy can be seen in table A-2. To construct the taxonomy, we hewed closely to prior studies of interest groups, including Walker [Reference Walker1991], Wright [Reference Wright1996], Goldstein [Reference Goldstein1999], Baumgartner et al. [Reference Baumgartner, Berry, Hojnacki, Kimball and Leech2009], Schlozman [Reference Schlozman, Maisel and Berry2010], and Heaney et al. [Reference Heaney, Masket, Miller and Strolovitch2012].)

Figure 3 presents a more systematic look at this change by graphically indicating the shifting mobilization of particular types of groups. Figure 3A shows, for each nominee, the number of labor, civil rights, and abortion groups that mobilized—these are the types of groups that have been most active in nomination politics. Also shown is the fit from nonparametric loess lines (i.e., locally estimated scatterplot smoothing). As can be seen, labor groups have been active over the entire period, but their mobilization rates have declined in the past 2 decades. Civil rights groups also have a long history of involvement, although their prime period of involvement was from the 1960s to the 1980s. Finally, the sizable rise of abortion groups is indicative of the transformation in groups now active in nomination politics. Taken together, the three loess lines show sequential “peaks” in mobilization for labor, civil rights, and abortion groups.

Figure 3.

Shifting composition of interest groups. A, Number of groups mobilized in three (overlapping) categories: labor, civil rights, and abortion. B, Liberal and conservative mobilization more broadly. The lines are locally estimated scatterplot smoothing (loess) lines.

In addition to characterizing groups by their policy mobilizations or favored industry, we can characterize many groups by their ideological polarity. For example, active abortion groups include liberal organizations such as NOW and NARAL and conservative groups like the National Right to Life Committee. Figure 3B depicts the trends in mobilization by liberal and conservative groups; note the scale of the vertical axis is different from figure 3A . The figure reveals a general increase in participation over time on both sides. But in the last period conservative mobilization has often outpaced liberal mobilization (which has trended downward in recent years), a pattern consistent with the increased emphasis in the conservative legal movement on the importance of judicial selection (Teles Reference Teles2008).

Moving from the specific to the general, it is also useful to categorize groups by their broader purposes. For every interest group that appears in our data, we placed them in the following categories: corporations/businesses, state/local groups, occupational groups, identity groups, public interest/citizen groups, and a residual category (“other”). Although professional and occupational groups have always outnumbered other organized interests in the larger pressure group universe, citizen groups now represent a larger proportion of national lobbying organizations in existence than ever before (Walker Reference Walker1991). According to Walker, citizen groups emerged at roughly twice the rate of occupational groups in the 2 decades following 1965. Walker attributes this rise to a number of causes, including the growth of a large, educated middle class, the emergence of new sources of political patronage willing to subsidize political organizations, and the steady expansion of the power and responsibility of the federal government (39). We refer to this distribution of different types of groups as the “interest group ecology.”

Do we see similar patterns in confirmation mobilization? Figure 4 examines the shift in the ecology over time. Each graph breaks down mobilization by group type and by era; the horizontal axis features the three eras of mobilization. In figure 4A the vertical axis depicts the total amount of mobilization in each period for a given class of groups. For example, in the 1930–69 period, occupational groups mobilized a total of 56 times. Changes in figure 4A also reflect the larger secular increase in mobilization over time. To account for this, the vertical axis in figure 4B depicts the total amount of mobilization for a given class/era pair, divided by the total amount of all mobilization in that era. Accordingly, the percentages are “normalized” by era.

Figure 4.

Changes in interest group ecology over time

Figure 4 shows that the patterns seen in Walker’s analysis of the interest group community at large also hold with respect to Supreme Court nominations. In particular, the figure reveals the striking increase in mobilization by identity and public interest/citizen groups; in the 1987–2017 period, these classes of groups combined accounted for about 90% of all mobilization. But while corporations and associations representing groups of businesses actively lobby the Supreme Court through the filing of amicus briefs, we find very little involvement by these groups in the confirmation process. Although unions and labor organizations have long been active in the process, groups on the business side have only recently entered the fray. The US Chamber of Commerce, for example, did not issue its first statement formally supporting or opposing a nominee until 1991 (during the Thomas nomination). Given this ecology, it is perhaps not surprising that in the modern period confirmation hearings tend to focus heavily on hot-button social issues like abortion rights.

Finally, one additional recent trend worth noting is the rise of “dark money” groups, such as the conservative groups Judicial Crisis Network and Americans for Prosperity (both of which appear in our data). Enabled by the Supreme Court’s decision in Citizens United (558 U.S. 310 [2010]), these groups raise large amounts of money from wealthy individuals who can now remain anonymous legally (Mayer Reference Mayer2017). The Judicial Crisis Network, for example, focuses on expensive media campaigns using paid advertisements in the states of key senators. And while conservative groups moved first to embrace dark money following Citizens United, the battle has now been joined by liberal groups, who spent millions in dark money in an (unsuccessful) effort to defeat the nomination of Brett Kavanaugh (Lee Reference Lee2018).

C. Interest Groups’ Choice of Tactics and Timing

Choice of Tactics. In addition to changes in the distribution of groups over time, changes in technology and politics over our period of study likely meant significant changes in the types of tactics that interest groups employed when mobilizing. Scholarly accounts of interest group lobbying tactics generally differentiate between inside advocacy, involving direct personal access and contact with legislators, and outside advocacy, usually defined as a strategy by interest groups to mobilize citizens outside the policy-making community to put pressure on public officials inside the policy-making community. For example, inside advocacy would include contacting a member of Congress personally, testifying in a congressional hearing, or contributing to a member’s campaign. Outside advocacy would include speaking with the press or running an advertising campaign. Finally, although it is similar in spirit to outside advocacy, we can also distinguish grassroots advocacy, in which groups directly mobilize the public to participate, for example, via a demonstration or letter-writing campaign.

For every interest group action covered in the reportage, we coded the type of tactic the newspaper reported, as well as whether the tactic was best described as inside, outside, or grassroots advocacy (or a residual category of “other”).Footnote ¹⁸ Figure 5 depicts the breakdown of tactics over time; figure 5A depicts raw counts of each type, while figure 5B normalizes the counts by the total amount of advocacy in each period.

Figure 5.

Changes in interest group tactics over time. A, the Y-axis depicts the total amount of mobilization in each period for a given class of groups. B, the Y-axis depicts the total amount of mobilization for a given class/era pair, divided by the total amount of all mobilization in that era.

Figure 5 shows a dramatic change in the choice of tactics over time. In the 1930–69 period, interest groups relied mainly on inside advocacy, which accounts for about 60% of the tactics employed in this time frame. The two most common inside lobbying tactics were sending a letter to members of Congress and testifying before the Judiciary Committee in formal hearings on the nomination; these two activities constituted about 40% of all activity in the early period. While outside advocacy accounted for only 19% of the lobbying activity in this time period, contact with the press was the third most prevalent tactic, constituting 14% of overall activity.

The ratio of inside lobbying to outside lobbying reversed in the period from Haynsworth (1969) to Scalia (1986). During this period, outside advocacy accounted for 40% of the tactics employed by interest groups, while grassroots activities constituted 18%. Contact with the press was the most prevalent lobbying tactic utilized by interest groups (32%), while testifying before Congress remained the second most utilized tactic (19%).

Finally, the most recent period shows the shift from inside tactics to outside and grassroots tactics is nearly wholesale. From 1987 to 2017, outside lobbying accounted for 51% of the tactics employed, with direct press contact representing the most used tactic, constituting 36% of all activity. In this period, grassroots lobbying constituted 23% of all tactics, with inside advocacy constituting only 12%.

It is possible that the shift from inside to outside tactics is simply due to the changing composition of groups over time (discussed above). Figure 6 examines this possibility. It focuses on the three most prominent classes of groups: identity groups, occupational groups, and public interest (citizen) groups. Each panel shows the distribution of advocacy (inside/grassroots/advocacy) for a given class in a given time period. (Note the vertical axes vary in each panel.) The figure shows a very similar pattern for each type of group. In the early period, inside tactics are predominantly used. The middle period sees a rough mix of all three. Finally, in the 1987–2017 period, outside and grassroots tactics predominate. It is thus clear that there has been a secular change in tactics driven by factors common to all groups, such as changes in the costs or benefits of mobilizing using outside tactics and grassroots campaigns.

Figure 6.

Changes in advocacy over time, by class of groups. Y-axes (which differ across the panels) depict the distribution of the total count of tactics (inside, grassroots, or outside) chosen by the given group type/era combination indicated at the top of each panel.

D. What Predicts Mobilization?

Taken together, the tactics and timing data reveal three notable trends. First, over the 80-year period, we observe a shift from inside lobbying to outside lobbying. Second, we observe a steady increase in the prevalence of grassroots lobbying tactics. This may reflect in part the technological advances that occurred over time. Third, groups have shifted toward immediate mobilization rather than waiting for hearings to commence.

What explains these shifts? In addition to changes in technology, we suspect they are attributable to the larger shifts in confirmation politics. Confirmation hearings during the earliest period represented important opportunities for senators to learn about the nominee and form or solidify their views. As such, the timing of interest group mobilization was focused primarily on the hearing itself as the principal venue to lobby Congress and spread the groups’ messages.

As the battles over Supreme Court nominations have become more ideologically driven and reminiscent of political campaigns, the hearings have more closely approximated a staged performance and taken on less significance as a result.Footnote ¹⁹ The new groups that entered politics during the 1970s and then became engaged in nomination politics took a different approach. They began to treat a nomination as a campaign, waged from the moment a vacancy emerged on the Court. The hearings remained a centerpiece for this campaign, but the bulk of the action occurred in the run-up to that increasingly staged moment of political theater. Thus, in the latter period interest group mobilization has primarily taken place before the confirmation hearing and largely revolved around framing the nominee through calculated messaging disseminated in the popular press.

For the final component of our analysis, we can leverage the implications of the patterns from our descriptive analyses to predict overall mobilization on nominees, as well as how mobilization changed over time. We can also leverage the theoretical foundation laid by studies of roll call voting on Supreme Court nominees, in particular the model developed in Cameron, Cover, and Segal (Reference Cameron, Cover and Segal1990). That model, as well as much subsequent work (see, e.g., Epstein et al. Reference Epstein, Lindstadt, Segal and Westerland2006; Cameron et al. Reference Cameron, Kastellec and Park2013), shows that senators are more likely to oppose nominees who are more ideologically distant, as well as those lacking in legal qualifications, or “quality.” We use these variables to uncover whether interest group mobilization displays similar tendencies.

In particular, the relatively sparse mobilization in the early period in our data set implies opportunistic mobilization. Given the reduced focus on ideology in the overall nomination and confirmation process, it seems plausible that the legal qualifications (which, in turn, are related to whether a scandal emerged for a nominee) of a nominee were a main driver of mobilization. In contrast, as ideology came to dominate the confirmation process, we saw above how both the ecology and timing of mobilization changed. This shift, in turn, implies a movement toward the ideology of the nominee increasingly driving mobilization.

Do the data support this account? To test it, we return to the counts of mobilization shown in figure 1. As our main dependent variable, we use the overall number of unique groups that mobilize per nomination. Because the theoretical expectations may apply equally as well to mobilization in opposition to a nominee (particularly with respect to quality), we also employ that measure as a dependent variable; in the interests of space, we present those regressions in the appendix (see Sec. A.2).

The nature of the data makes estimation somewhat tricky. The number of groups is a count variable and also exhibits overdispersion; thus, a negative binomial specification is appropriate. The data, of course, are also dynamic. However, the time series is “irregular,” as nominations occur at irregular points in time. While there are existing models for dynamic count data (see, e.g., Brandt et al. Reference Brandt, Williams, Fordham and Pollins2000), they are not designed for such irregular data. Accordingly, we adopt the following strategy. To account for autocorrelation, we include the following predictors in every model.Footnote ²⁰ First, we create a time indicator that takes the value 1 in 1930 and then adds 1 for every subsequent year. Next, time difference captures the number of years between the current nomination and the previous nomination (nominations in which the prior nomination occurred in the same calendar year take the value 0). Next, we include lagged total groups, which take the level of mobilization in the previous nomination. Finally, to account for the irregularity of nominations, we include the interaction of lagged total groups and time difference, which we call lag × time difference.

Our two main predictors of interest are ideological extremity and quality. The former is based on the NOMINATE-Scaled Perceptions (NSP) scores developed by Cameron and Park (Reference Cameron and Park2009); the scores indicate the perceived ideology of each nominee at the time of nomination, scaled into NOMINATE space. As with NOMINATE, more negative scores indicate more liberal nominees, while positive scores indicate more conservative nominees. To capture extremity, we take the absolute value of this measure, such that higher scores mean a more extreme nominee.Footnote ²¹ For quality, we employ the standard measure based on content analysis of newspaper editorials first developed in Segal and Cover (Reference Segal and Cover1989) and Cameron et al. (Reference Cameron, Cover and Segal1990).

In addition to these predictors, it is important to account for the number of interest groups in existence at each nomination. While there exist several studies that track the interest group environment at various points in time (see, e.g., Schlozman Reference Schlozman, Maisel and Berry2010; Bevan et al. Reference Bevan, Baumgartner, Johnson and McCarthy2013), none appears to go back as far as 1930. As a proxy, we instead use the total number of amicus briefs filed in a given year with the Supreme Court, which should closely parallel the number of active interest groups.Footnote ²² We normalize this variable by taking the log of amicus briefs for each year.

Before turning to the results, given both the structure of the data and the need to employ this number of predictors, combined with the fact that we have only about 50 observations over an 80-year period to work with, a bit of caution is warranted at the outset. We are pushing the data to their limits, and thus our causal conclusions can only be suggestive.

E. Regression Results

Table 2 presents four regression models, in which the dependent variable is the total number of groups that mobilized for each nomination. (Because the amount of mobilization during the Bork nomination is such an outlier, we exclude this observation from all the regression models.) Model 1 examines the entire sample of nominees. We find that total mobilization significantly decreases as a nominee’s quality increases and that mobilization increases as the nominee becomes more extreme. However, the coefficient on extremity is measured imprecisely. (We also find that, accounting for time, higher levels of amicus briefs are not associated with higher mobilization.)

Table 2.

Negative Binomial Models of Mobilization

Note.—In each model, the dependent variable is the overall number of groups mobilizing in each nomination. Standard errors in parentheses.

⁺ $p<.10$ .

* $p<.05$ .

Of course, pooling the nominees together may mask the predicted changes in mobilization over time. To measure changes over time, we first break down the data into two periods: before and after 1970. We use this cut point for both theoretical and practical reasons. Theoretically, this corresponds to the break between the first and second eras we identified above. Practically, it allows for enough observations (21) in the post period to run a regression model. Model 2 in table 2 includes the same predictors as model 1 but is run only on the pre-1970 nominees. It shows that compared to model 1, the coefficient on quality is of larger magnitude, while the coefficient on extremity is smaller and is measured with even greater uncertainty. These results are consistent with quality being a better predictor of mobilization in the early period. Model 3 uses only the nominees in the post-1970 period. Quality remains a significant predictor, but of perhaps more interest is that the coefficient on extremity is both significant and of comparable magnitude.

Finally, model 4 allows for a more flexible examination of changes over time by including the interactive terms extremity × time and quality × time (along with the respective main effects). Owing to the number of interaction terms in what is a nonlinear model, the coefficients on the key predictors are not readily interpretable. Accordingly, we turn to a simulation/graphical approach. First, we simulate the coefficients from model 4 to generate 1,000 draws of each coefficient.Footnote ²³ Then, for every year, we generate the predicted number of groups expected to mobilize, varying (in turn) the quality and extremity of a nominee.

We present the results in figure 8. Beginning with figure 8A , we first simulate the predicted level of mobilization by dividing quality into “low” and “high” levels. Specifically, we fix all the other predictors at their mean levels in the data. We then set low and high quality at the 25th and 75th percentiles of the quality measure in the data. Finally, for both conditions, we calculate the predicted level of mobilization, using the simulated coefficients from model 4 (including the constant). Using simulations, rather than just the coefficients from the model, allows us to generate uncertainty estimates. In the interest of graphical clarity, we just present the mean prediction for every year; we return to uncertainty shortly.

Figure 8.

Predicted mobilization by high and low levels of quality and ideological extremity: A, quality levels; B, extremity levels; C, quality differences; D, extremity differences. Right plots show the difference between the two lines in the respective left plots; the shaded areas depict 90% confidence intervals.

Figure 8A presents the predicted level of mobilization over time, for both low-quality and high-quality nominees. In line with the overall trend in mobilization, we see that mobilization has increased for all types of nominees. Of interest, however, is that predicted mobilization has always been higher for low-quality nominees. Figure 8C depicts the difference between the high- and low-quality predictions, along with the 90% confidence interval of the difference (so as to approximate a one-tailed test). The figure shows that early on the difference in mobilization across quality was statistically significant, but it no longer is. Overall, while low quality has generally predicted overall mobilization levels, the relationship between the two has become noisier over time.

Next, figures 8B and 8D present parallel analyses for ideological extremity. Here we fix quality at its mean level in the database and then set low and high extremity at the 25th and 75th percentiles of the extremity measure in the data. Figure 8B shows a different pattern for ideology than for quality. Early on, ideological extremity was not a significant predictor of mobilization, with no differences across high- and low-extremity nominees. Over time, however, the predicted mobilization for more extreme nominees has increased substantially, relative to the slower growth seen for low-extremity nominees. As of 2005, the predicted mobilization for a high-extremity nominee was 34 groups, compared to 16 for a low-extremity nominee—a substantively significant difference. Finally, figure 8D depicts the difference across the two types and the 90% confidence interval of the difference. The confidence intervals are fairly wide in the later period but still exclude 0.Footnote ²⁴

As noted earlier, the data are sufficiently limited and the models are sufficiently saturated that our conclusions are necessarily tentative. Nevertheless, we believe the regression results, combined with the data, on the change in tactics discussed above at least suggest the following interpretation. Before the mid-1980s, there were groups that opposed nominees made by presidents of both parties. But it appears that these groups mobilized opportunistically: intense mobilization occurred only when the groups could exploit an adverse shock to the nominee’s perceived quality—for example, in response to a scandal. As time went on, this changed. While quality still may play a role in mobilization decisions, ideology is now as important or even more important. Groups ideologically hostile to the nominee now almost invariably mobilize.Footnote ²⁵ And, in turn, groups who support the nominee have also joined the fray, giving us the rough parity in mobilization seen in figure 1.

A. What Happened

In a nutshell, from the 1930s through the 1960s the interest group world of Supreme Court nominations was characterized as follows:

• • a small number of active groups, often labor unions and civil rights groups on the liberal side and old right groups on the other side

• • infrequent mobilization, often sparked opportunistically by scandals and low-quality nominees

• • somewhat restrained inside-oriented tactics, focused on the hearings

This world is of a piece with that described by Pendleton Herring, V. O. Key, David Truman, and Robert Dahl in other settings. We call this the era of textbook pluralism.

By the early 1970s, the era of textbook pluralism was drawing to a close. In the decade and a half that followed, mobilization became more frequent, involving larger numbers of groups, with liberal groups often dominating the mobilizers. By about the mid-1980s, a new world was in place. It was characterized as follows:

• • a much larger number of active groups, often oriented around identity or public interest

• • routine mobilization for almost every nomination, sparked particularly by ideologically extreme nominees

• • rough parity in liberal and conservative groups

• • extremely vigorous outside-oriented tactics, organized as a political campaign lasting from the vacancy until the confirmation vote

The heightened scale, intensity, pace, and ferocity of the new world of appointment politics is textbook pluralism on steroids. It suggests a new appellation: “hyperpluralism.”

Two questions immediately present themselves: First, why? Why did textbook pluralism end, why did hyperpluralism emerge, and why did it take the form that it did? Second, so what? What difference does the shift from textbook pluralism to hyperpluralism actually make? Is it all dramatics without substance, or are there genuine consequences? Answering these questions lies well beyond the scope of this article. Still, we offer some observations and conjectures if only to lay down markers for future work.

B. Why Did the Transition Occur?

In her study of lower-court appointment politics, Scherer (Reference Scherer2005) chronicles interest group politics that are in some ways similar to those we document, although in some ways different. She reveals a transition from humdrum patronage politics before the late 1960s to the current fiery politicization of lower-court appointments sparked by issue activists. Today’s appointment activists, she argues, favor a take-no-prisoners politics, and senators (and the president) cater to them.

Her account raises several puzzles: Where did the issue activists come from, why are they so fixated on judicial appointments, and why are senators and presidents so beholden to them? She offers provocative answers, some of which are echoed in recent scholarship, for example, on the rise of the conservative legal movement (Teles Reference Teles2008; Southworth Reference Southworth2009). First, the issue activists responded to landmark judicial decisions of the 1960s and 1970s, either opposing offensive decisions or supporting attractive ones. Second, activism around judicial nominations afforded the enthusiasts a means to undermine offensive judicial decisions (from the viewpoint of opponents) or bolster precious favorable ones (from the other viewpoint). Third, the party reforms of the 1970s drove nonideological party professionals from the field and essentially turned over those organizations to the issue activists (see, e.g., Shafer Reference Shafer1988; Rosenfeld Reference Rosenfeld2017). At present, the activists command organizational and financial resources essential for successful campaigns, hence the eager compliance of the president and senators with the diktats of the issue activists. Finally, Scherer notes that the process is self-reinforcing: “Party-polarized nominations … in turn engage in party-polarizing voting on the bench” (Reference Scherer2005, 11).

Thus, in many important respects, the trends we find with respect to Supreme Court nominations parallel those seen in lower-court nominations. Bell (Reference Bell2002) and Steigerwalt (Reference Steigerwalt2010), for example, trace the rise of contentious politics in lower-court confirmations to the Reagan administration, an emergence that slightly lags the growth of groups in the 1970s but not by much. In addition, both scholars note a shift from “formal” interest group tactics, such as testifying before the Judiciary Committee, to “informal” tactics, such as mobilizing public opinion—this shift is directly analogous to the shift from inside tactics to outside/grassroots tactics that we document. Similarly, in their study of interest group participation in lower-court hearings before the Judiciary Committee from 1945 to 1992, Flemming, MacLeod, and Talbert (Reference Flemming, MacLeod and Talbert1998) find that citizen groups became more likely over time to participate than professional groups. Finally, it is notable that the introduction of the “nuclear option” for judicial nominations (i.e., eliminating the 60-vote threshold for confirmations) was exercised first for lower-court nominees in 2013, before being adopted for Supreme Court nominees 4 years later.

But there are important differences in contemporary interest group politics between Supreme Court nominations and lower-court nominations. For example, as we showed, interest group activism around Supreme Court nominees now resembles a political campaign, with immediate mobilization no matter who the nominee is. In contrast, mobilization for lower-court nominees remains conditional; instead of opposing all nominees, interest groups pick and choose their battles in an effort to block the most objectionable nominees; this effort, in turn, produces a high likelihood of delaying a nomination to death in the Senate (Scherer, Bartels, and Steigerwalt Reference Scherer, Bartels and Steigerwalt2008; Steigerwalt Reference Steigerwalt2010). We believe this divergence, in turn, can be traced to the differing public salience of lower-court nominations versus Supreme Court nominations; the former go largely unnoticed by the public (in part because they are so numerous), while the latter are now high-salience events (in part because they are relatively rare).

Still, Scherer’s overall story, in combination with the broader reconsideration of the nexus between political parties and interest groups in the study of American politics (Bawn et al. Reference Bawn, Cohen, Karol, Masket, Noel and Zaller2012), provides a framework for understanding the transition from the world of textbook pluralism to today’s hyperpluralism. Future work might well scrutinize this account, tightening the theoretical linkages, investigating the empirical implications in more detail, and tying the changes to larger movements in American politics and society.

C. What Difference Does Hyperpluralism Make?

The interest group transformation in appointment politics almost surely has real consequences. We suggest impacts in four areas: (1) presidential selection of nominees, (2) increased contentiousness and polarization in confirmation voting in the Senate, (3) increased ideological polarization on the Court itself, and (4) increased danger of conflict between the Court and other branches. Needless to say, our brief discussion can only be suggestive.