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Publicly Available Published by De Gruyter February 14, 2022

The Rising Electoral Role of Polarization & Implications for Policymaking in the United States Senate: Assessing the Consequences of Polarization in the Senate from 1914–2020

Carlos Algara and Savannah Johnston
From the journal The Forum

Abstract

The dramatic Democratic victories in the 2021 Georgia U.S. Senate runoffs handed Democrats their first majority since 2015 and, with this, unified Democratic control of Washington for the first time since 2011. While Democratic Leaders and President Joe Biden crafted their agenda, any hope of policy passage rested on complete unity in a 50–50 Senate and a narrow majority in the U.S. House. Against this backdrop, the 117th Senate is the most polarized since direct-election began in 1914 and, by popular accounts, the least deliberative in a generation. In this article, we examine the implications of partisan polarization for policymaking in the U.S. Senate throughout the direct-election era. First, we show that greater polarization coincides with more partisan Senate election outcomes, congruent with recent trends in the House. Today, over 90% of Senators represent states carried by their party’s presidential nominee. Secondly, we show that polarization coincides with higher levels of observable obstruction, conflict, partisan unity, and narrower majorities. Lastly, we show that this polarization coincides with lower levels of deliberation in the form of consideration of floor amendments and committee meetings. Taken together, we paint a picture of a polarized Senate that is more partisan, more obstructionist, and less deliberative.

1 The Popular Account: A Polarized & Obstructionist United States Senate

If the Senate isn’t going to be the most important venue for addressing our biggest national problems, where is that venue? We have rules designed to strengthen the hand of individual senators, not to the end of obstruction, but rather to ensure full debate and engagement with dissenting points of view.

-U.S. Senator Ben Sasse (R-NE), 11/4/2015

The US Senate has long been known as the “greatest deliberative body in the world.” But in today’s Senate, there’s very little deliberation, very little debate. Senators spend more time debating whether to debate than they do actually debating the issues.

-U.S. Senator Jeff Merkley (D-OR), 5/6/2021

Providing an exclamation point for the contentious 2020 election cycle, which saw former Democratic Vice President Joe Biden become only the seventh challenger to unseat an incumbent President since the Civil War, the dramatic Democratic victories in the 2021 Georgia U.S. Senate runoffs handed Democrats control of the U.S. Senate for the first time since 2015.[1] Coupled with the re-election of a narrower than expected 222–213 House Majority in the 2020 elections, Democrats secured unified control of Washington for the first time since 2011.[2] While Democratic leaders and President Joe Biden craft their agenda, any hope of policy passage rests on complete unity in a 50–50 Senate and a narrow majority in the U.S. House. Against this backdrop, the 117th Senate is the most polarized since direct-election began in 1914 and, by popular accounts, the least deliberative in a generation.

Both contemporary pundits and Senators themselves note that romanticized description of the Senate as the “world’s greatest deliberative body” largely fails to describe the contemporary nature of the upper chamber in the 21st century (Smith 2010; Theriault and Rohde 2011). In his maiden speech to the United States Senate, which came 11 months into his first year in the Senate in deference to past tradition in the upper chamber, freshman Senator Ben Sasse (R-NE) bemoaned the lack of deliberation and suggested that the absence of “principle governing” contributed to a sentiment that the “people despise us all because we’re not doing our job.” Indeed, Congress’ approval rating sits at a lowly 21% as of October 2021. This would be front-page news in a more normal era, yet a low public approval rating is par for the course for Congress over the past two decades (Algara 2021). In a similar sentiment about six years later within the context of filibuster reform, Senator Jeff Merkley (D-OR) posited that the contemporary Senate was anything but “greatest deliberative body in the world” and that the Senate deliberated over debate itself rather than substantive policy issues, finishing with the point that “it’s time to restore the Senate as a deliberative body, a place for great debate and meaningful discussion.” How did the world’s most August deliberative body become, in the eyes of the public, neither deliberative nor productive – in short, despised? The late Senator John McCain (R-AZ) blamed the collapse of regular order. After infamously voting no to repeal the Affordable Care Act, McCain decried the Senate process of drafting proposed legislation “behind closed doors … then springing it on skeptical members, trying to convince them it’s better than nothing, asking us to swallow our doubts and force it past a unified opposition.” He urged the Senate to “return to the correct way of legislating,” sending bills to committee, holding hearings, and ultimately crafting laws that could be passed with bipartisan support.”[3]

Other Senators have laid the blame on the rise of rank partisanship. Senator Jeff Flake (R-AZ) bemoaned the state of compromise in the Senate to CBS’s Scott Pelley shortly before retiring. “There’s no value to reaching across the aisle. There’s no currency for that anymore. There’s no incentive… It’s this whole tribal nature of politics that becomes shirts and skins. It’s us-versus-them. There’s no room for compromise or doubt.” Loyalty to party, not bridge building, is the order of the day.[4] Neither perception – that partisanship has infected the Senate and regular legislative order is the victim – are misguided. The U.S. Senate is, in fact, at its highest level of polarization since the end of the Civil War and, as a consequence, a more partisan institution. This paper will show that greater ideological polarization provides three key implications for the Senate. First, greater polarization coincides with more partisan Senate elections, to the point that these elections are the most partisan since at any point since full implementation of the 17th amendment provided for the direct-election of Senators in 1914. Indeed, today’s Senate elections mirror those for the U.S. House in the degree that partisanship predicts electoral outcomes, with the quality of candidates mattering far less than the party they identify with. Second, parties in the Senate have become more unified and cohesive, while majorities are smaller and similarly unified. Finally, the contemporary Senate is far more obstructionist and less deliberative than the Senates of the past. We draw on various prominent legislative theories to descriptively explain why we observe these key implications as the Senate polarizes.

2 Examining Partisan Polarization in Congress, 1867–2022

The traditional accounts of the U.S. Senate are largely tied to the depiction of the Senate as “the greatest deliberative body in the world” that is “less likely to be captured by the trends of the day than the House” (Smith 1989; Theriault and Rohde 2011). This depiction of the U.S. Senate is one of a deliberative body where partisan control of the agenda by the majority party is weaker than the majoritarian U.S. House and individual legislators, and the committees in which they are organized are largely autonomous agents in the policymaking process (Matthews 1959; Smith 1989). Compared to the U.S. House of Representatives, the upper chamber is largely cast as an institution in which the majority party lacks the power needed to unilaterally manipulate rules and pass legislation given the strong degree of procedural rights afforded to individual legislators (Den Hartog and Monroe 2011; Smith, Ostrander, and Pope 2013). Observing the Senate over a half century ago, Matthews (1959) posited that the Senate is a place where partisan influence is relatively weak and “there is a great pressure for conformity” in a Senate in which norms of bipartisanship and independence are prevalent in the chamber.

Within the context of the contemporary Senate, these accounts have largely given way to a depiction of the Senate that is both as polarized (Theriault 2008) and as partisan (Roberts and Smith 2003; Smith 2007) as the majoritarian and partisan-centered House. Popular media accounts, and retiring Senators themselves, note the changing nature of the institution. In a particularly high profile and surprising retirement prior to the 2010 midterm elections, U.S. Senator Evan Bayh (D-IN) lamented a Senate occupied with “too much narrow ideology and not enough practical problem solving” and urged “significant reform” given that the “people’s business is not getting done.”[5] For our purposes, we posit that the Senate is experiencing ideological polarization not seen since the conclusion of the Civil War, leading to more partisan outcomes and negative implications for policymaking that make the Senate a less deliberative, more contentious, and less productive institution. To situate the contemporary 117th Senate in historical context with respect to polarization, Figure 1 plots the standard measure articulating partisan polarization in Congress by articulating the absolute difference in the ideological locations between the median Democratic and Republican legislators on first dimension DW-Nominate scores for both the House and Senate since the Civil War.

Figure 1: 
Post-civil war ideological polarization in the U.S. Congress.

Figure 1:

Post-civil war ideological polarization in the U.S. Congress.

As Figure 1 shows, the contemporary 117th Senate is not only the most polarized since the 1913 passage of the 17th amendment providing for the direct-election of Senators by voters rather than state legislators but also the most polarized since the immediate aftermath of the Civil War. Moreover, the contemporary Senate mirrors the House in the degree of ideological polarization between the Democratic caucus and Republican Conference. The 117th House is only 4% more polarized than the 117th Senate.[6] This suggests that despite not being subjected to redistricting and potential partisan gerrymandering like the House, the Senate experiences similar levels of heightened partisan polarization. Indeed, following the relatively depolarized “Textbook Congress” era of the 1970s (Theriault 2008), the Senate experienced largely monotonic growth in polarization due to the increased salience, and elite partisan sorting, along social issues such as Civil Rights (Carmines and Stimson 1989), income inequality (McCarty, Poole, and Rosenthal 2006), and abortion (Adams 1997). This culminates in a contemporary Senate animated by two parties with fiercely contrasting ideological agendas and preferences on public policy.

3 Greater Congruence: The Electoral Implications of Polarization

Scholars argue that partisan polarization on Capitol Hill helps shape the local candidate choices facing voters in congressional elections by making elections more partisan-centered, rather than candidate-centered, contests (Algara 2019; Jacobson 2015; Stone 2017). As Stone (2017) posits, greater ideological polarization in Washington should increase partisan differences between local congressional candidates at the expense of candidate-centered characteristics.

Polarization and its effects on party brands and awareness should increase the link in voters’ minds between individual candidates and their parties, such that voters are more likely to recognize that voting for a Democrat is a vote for more liberal national policy, and a vote for the Republican candidate running in a particular district is a vote for more conservative policy. (p. 78)

We expect that greater polarization strengthens and clarifies the link between local candidates and the national ideological platforms espoused by their parties, which, in turn, heightens the congruence between constituent preferences and electoral outcomes. A simple bivariate test of this proposition would assess how much of the electoral outcomes in congressional elections is explained by constituency partisanship (Amlani and Algara 2021; Jacobson 2015). To that end, we assess a simple bivariate model modeling the two-party voteshare won by the Democratic candidate running a given congressional election as a function of the constituency’s (i.e., congressional district for the U.S. House and state for the U.S. Senate) partisan preferences measured as the proportion of the two-party voteshare won by the Democratic presidential candidate in the most recent election.[7] We estimate this bivariate model for the U.S. House from 1900 to 2020 at the district level and for the entire direct-election period of the U.S. Senate from 1914 to 2020 at the state and county-level, respectively.

Figure 2 presents results of these election year models over varying degrees of ideological polarization found in the chamber during the respective years.[8] As one can see, there is clear evidence that as both the House and Senate polarize, the greater the salience of partisanship in shaping the ultimate electoral outcome. Indeed, in the 2020 congressional elections, constituency partisanship explains about 97% of the variation in House election outcomes, 97% in the county-level variation in Senate election outcomes, and 90% in state-level variation in Senate election outcomes, respectively. These results show that without accounting for candidate-centered predictors of election outcomes, such as incumbency or candidate quality, constituency partisanship explains an overwhelming degree of variation in congressional election outcomes in both chambers. Moreover, the relatively higher-profile contexts of the Senate mirror the lower-profile contexts of the House with respect to the role of partisanship in shaping outcomes, with both levels of electoral competition experiencing similar degrees of partisanship (Gronke 2001).

Figure 2: 
The increasing explanatory power of partisanship in congressional election outcomes.

Figure 2:

The increasing explanatory power of partisanship in congressional election outcomes.

Another way to articulate the growing salience of partisanship in determining congressional election outcomes is to assess the average absolute deviation in the proportion of the vote won by the local congressional candidate and their national party’s presidential nominee in the constituency. One would expect that if polarization clarifies the link between the local congressional candidate and their national party, then the deviation in the proportion of the vote won in the congressional district, state, or county should approach zero as the two parties polarize. This signifies that not only is straight-ticket voting increasing as the deviation approaches zero, but also that local candidates are no longer able to out-pace or under-perform their party’s presidential candidate at the top of the ticket during periods of pronounced partisan polarization. Figure 3 articulates the average deviation between the local House or Senate candidate and their party’s presidential nominee as each chamber becomes more polarized. As the House and Senate become more polarized, the deviation between the local candidate and the national party’s presidential nominee approaches zero. During the 2020 elections, which took place during the most polarized period in congressional history since the Civil War, the average deviation between the local candidate and the national party’s presidential nominee was 2% in both the House and Senate. This analysis shows that as ideological polarization increases, the ability of the local candidate to over or under perform their party’s baseline performance in the national presidential election in the constituency (i.e., district, state, or county-level) largely diminishes. As such, partisan performance, independent of the candidates, at the presidential and congressional level is largely congruent as the two parties become more polarized on Capitol Hill.

Figure 3: 
Lack of deviation in partisan electoral performance as congress polarizes.

Figure 3:

Lack of deviation in partisan electoral performance as congress polarizes.

Up to this point, we show that pronounced ideological polarization between the two parties in Washington profoundly shapes the increasing role of partisanship in both explaining and shaping electoral outcomes. During periods of great partisan polarization, the link between local candidates and the national party becomes so pronounced that candidate-centered characteristics do not further explain our understanding of congressional elections during the polarized era and local candidates are no longer able to substantively deviate from the performance of their party at the top of the ticket. To further build on this, we now assess the degree of congruence between the partisan preferences of constituents and the party of the members of Congress (MC) and U.S. Senators they send to Washington as both chambers become more polarized. In 4, we show the proportion of legislators that correctly “match” the partisan preferences of their constituents–with the “match” simply articulating the proportion of both Democratic Senators (MCs) representing Democratic states (districts) and Republican Senators representing Republican states (districts).[9]

Figure 4 shows that greater polarization in the House and Senate corresponds with greater match between district partisanship and the party of the MC and U.S. Senator they elect. Following the 2020 elections, 94% of MCs and 93% of U.S. Senators were elected in states carried by their party’s presidential nominee in the 2020 presidential election. Following the conclusion of the 2020 presidential election, only Democratic U.S. Senators Sherrod Brown (OH), Jon Tester (MT), and Joe Manchin (WV) represent states carried by former Republican President Donald Trump during the 2020 election. Republican U.S. Senators Susan Collins (ME), Ron Johnson (WI), and Pat Toomey (PA) represent states carried by Democratic President Joe Biden.[10] To this point, the 117th Senate also features the lowest number of split Senate delegations consisting of one Democratic and Republican Senator during the entire direct-election era, with only the six states of Maine, Montana, Ohio, Pennsylvania, West Virginia, and Wisconsin sending a Senator of each party to Washington.[11] This is a stark decline from the high water mark set during the far less polarized 96th Senate, which saw 27 states send a split-party delegation to the United States Senate. Taken together, Figure 4 shows that at no point since 1900 has constituent partisanship matched legislator partisanship in the U.S. House, and, perhaps most strikingly, at no point since the direct-election of Senators began in 1914 has constituent partisanship and the party of their Senator been more closely matched. This shows that the most polarized House and Senate since the Civil War will consist of legislators that overwhelmingly represent the partisan preferences of their constituents back at home, with close to 95% of legislators in both chambers sharing the partisan preferences of the districts that elected them.

Figure 4: 
Greater congruence in constituency & legislator partisanship as Congress polarizes.

Figure 4:

Greater congruence in constituency & legislator partisanship as Congress polarizes.

Lastly, these heightened partisan dynamics during periods of increased ideological congressional polarization should not only shrink the number of competitive seats available to each party (Abramowitz and Webster 2016; Jacobson 2015) but also the size of the majority party in both the House and Senate. As Lee (2016) posits in her seminal work Insecure Majorities, both parties in the contemporary polarized Senate facesthe “stubborn reality” of heightened two-party competition and narrow majorities, particularly since the post-1994 Republican Revolution. As a consequence, the contemporary Senate is centered on uncertainty about future control of the chamber, greater partisan conflict, and the continuous partisan messaging battle surrounding both parties (Lee 2011). As we shown previously, polarization strengthens the partisan continuity between constituency preferences and the party of the MC they elect, which gives way to a remarkable degree of nationalized congressional elections not seen since the Civil War (see Amlani and Algara 2021; Hopkins 2018; Sievert and McKee 2019, for additional evidence of this nationalization). Coupled with greater urban-rural partisan polarization – both Democratic urban centers and Republican rural areas becoming much more partisan (Rodden 2010) – the number of battleground districts and states deciding control of both chambers of Congress is shrinking, leading to greater uncertainty over the majority in the next Congress and smaller majorities in the present Congress.

Figure 5 shows this reality by plotting the majority size differential over degrees of polarization in the House from 1898 to 2020 and the Senate from 1912 to 2020. In both the House and Senate, there is clear evidence that more polarized chambers are associated with smaller majority size. This suggests that not only does greater polarization correspond with more partisan elections and greater match between constituency and legislator partisanship but also with smaller majority sizes in both chambers. During the 117th Congress, the Senate features an even 50–50 split between the two parties with Vice President Harris breaking the tie and handing the majority to Senate Democrats. The House features a narrow 4 seat Democratic majority.[12] To this point, we have shown that the Senate does not escape the level of polarization that plagues the House and that greater polarization correlates with similarly situated partisan elections in both chambers, with Senators increasingly tied to the electoral fortune of their national party and representing partisan friendly states. Building on arguments in the literature review (i.e., Lee 2016), we also demonstrated that the polarized contemporary Senate features both smaller majorities and, by extension, uncertainty regarding the majority in the next Congress. In the following section, we turn from assessing the electoral implications of polarization to the policymaking implications of this polarization in the U.S. Senate, a chamber marked by both stark ideological polarization between the parties and Senators elected from increasingly partisan constituencies.

Figure 5: 
Shrinking partisan majorities as Congress polarizes.

Figure 5:

Shrinking partisan majorities as Congress polarizes.

4 The Policy Making Implications of U.S. Senate Polarization

4.1 Greater Legislative Conflict, More Unified Parties, & Obstruction

The traditional model of congressional parties posits that the “legislative parties speak not as two voices but as a cacophony of blocs and individuals fulfilling their own definitions of the public good” (Stokes and Miller 1962). Lacking the formal mechanisms to coerce party discipline in the legislature, such as control of nominations or access to party fundraising networks, scholars have remarked that American congressional parties lack responsibility (American Political Science Association 1950), unity (Mayhew 1974), and electoral coherency before the eyes of the voters (Bartels 2000). With the advent of pronounced polarization between the congressional parties over the course of the 20th century, scholars have updated their view of the weak party model on the basis of increased partisan differences in ideological platforms. Congressional parties today are characterized as not only polarized around competing ideological agendas (McCarty, Poole, and Rosenthal 2006), but also by a greater sense of responsibility that clarifies the stark partisan choices before voters (Hetherington 2001). We show that the contemporary 117th Senate is not only the most polarized Senate since the Civil War, it is also the most reflective of the partisan preferences of states, suggesting voters respond to greater polarization in Washington by engaging in greater partisan-centered electoral accountability.

In terms of deliberation and control of the legislative agenda, scholars have also posited that the emergence of polarized, electorally coherent, and responsible parties privileges majority party leaders with greater control of the legislative agenda and, by extension, a greater monopolization of power by the majority. For example, Rohde’s (1991) conditional party government (CPG) theory posits that with greater intraparty ideological homogeneity and interparty conflict, the greater the propensity by majority party legislators to grant sweeping agenda setting powers to their party leaders and collective party organizations. Similarly, Cox and McCubbins’s (2005) procedural cartel theory (PCT) argues that the majority party delegates both positive and negative agenda control to majority party leaders in order to strengthen the partisan brand that serves as the key basis for an individual member’s re-election. While the Senate and House differ on procedural grounds, with individual Senators having greater procedural rights on the floor than MCs (Oleszek et al. 2016), previous work finds that both the House and Senate majority monopolize agenda control in the policymaking process to a very similar degree (Gailmard and Jenkins 2007).

While both prominent theories of legislative organization conflict on the degree to which ideological polarization is a necessary condition for the delegation of agenda setting power to majority party leaders by majority party members, both theories suggest that polarization may lead to greater legislative conflict and party unity.[13] First, CPG posits that greater polarization should coincide with greater agenda setting powers for the majority, setting the stage for less minority party involvement in the policymaking process and more legislative party votes that divide both parties. In order to overcome the minority party opposition that will be apparent in a polarized Senate, the majority must stand unified to pass the agenda brought forth by party leaders. Secondly, PCT posits that delegation of agenda control power to majority party leaders by members is rooted in protecting the electoral party brand, which we show is far more salient in congressional elections during periods of greater ideological polarization. As such, in a polarized Senate, the minority faces a stark incentive to oppose this attempt by the majority to strengthen the party brand that will serve as the overwhelming electoral basis by which majority Senators seek re-election given the almost complete role party plays in determining election outcomes.

To that end, we test the relationship between the partisan polarization and legislative conflict, measured in the standard way as the proportion of the roll–call votes classified as party unity votes that divide at least half of the two parties (Rohde 1991). Focusing on the Senate, Figure 6 shows that as the Senate polarizes so too does the degree of ideological conflict between Senate Democrats and Republicans, mirroring a similar pattern in the majoritarian U.S. House. Figure 7 plots the relationship between ideological polarization and partisan unity polarization, defined as the difference in mean legislator party unity scores between the two parties, with a maximum score of 1 indicating that the average member of both parties votes the party line and against the other party on all party unity votes dividing the chamber.[14] As Figure 7 shows, greater polarization solidifies party unity and leads to greater roll-call unity differences between both the majority and minority. The parties become increasingly cohesive voting blocs in the Senate, and the minority routinely seeks to use floor votes as a way to distinguish itself from the majority party agenda.

Figure 6: 
Great polarization & partisan votes in the U.S. Senate.

Figure 6:

Great polarization & partisan votes in the U.S. Senate.

Figure 7: 
Great polarization & party unity in the U.S. Senate.

Figure 7:

Great polarization & party unity in the U.S. Senate.

The development of more legislative conflict and cohesive voting blocs during periods of greater polarization also presents implications for how unified the majority party must be in the contemporary Senate. As we show previously, the polarized Senate is one of smaller majorities and greater legislative conflict between the parties. To pass the legislative agenda, Senate majority leadership in the contemporary Senate must increasingly rely on the unity of its members on the floor in the face of a more cohesive, unified, and polarized minority party. Qualitatively, this is seen in the first session of the current 117th Senate, with Senate Majority Leader Chuck Schumer (D-NY) needing all 50 Democratic votes to overcome unified Republican opposition on the American Rescue Plan Act of 2021, the key component of the 100 day agenda proposed by newly elected Democratic President Joe Biden.[15] Moreover, other key planks of President Biden’s legislative agenda for the 117th Congress, such as the Build Back Better Act, are subject to prolonged negotiations within the majority party. In other words, Democratic Senators have greater individual intra-party bargaining power in the face of unified Republican opposition in a 50–50 Senate. Without similar unity on these legislative items, the Democratic majority in the Senate will fail to pass President Biden’s legislative agenda heading into the 2022 midterm elections.

Figure 8 shows that the 117th Senate should follow a similar pattern as past polarized Senates, with greater polarization coinciding strongly with a cohesive and unified Senate majority on the floor. As Figure 8 shows, the average majority party Senator is a far more loyal partisan during periods of greater polarization, in many cases mirroring the level found in the majoritarian U.S. House. The average majority party Senator earns a party unity score of 0.95 during the more polarized Senates. Indeed, during the last two completed Senates (i.e., the 115th & 116th Senates), the average majority party Senator voted with their party over 97% of the time on votes that divided both parties. Taken together, this section lends support for the proposition that greater polarization coincides with greater conflict. Increased polarization correlates with greater unity differences between both the majority and minority parties that occupy the Senate. Moreover, as PCT would suggest, given the greater reliance on the partisan brand during the polarized era, the minority party increasingly votes against roll–call votes scheduled by majority leadership intending to build a record of legislative accomplishments in order to keep their majority. To overcome such opposition, the majorities steering more polarized Senates feature far more unified majorities necessary to pass their legislative agenda and build a partisan record of accomplishments designed to appeal to an increasingly partisan constituency (Cox and McCubbins 2005). The contemporary Senate is animated by intense partisan conflict featuring cohesive parties advocating distinct ideological positions on policy and majority parties needing almost total unity to pass their partisan priorities (Roberts and Smith 2003; Theriault and Rohde 2011).

Figure 8: 
Great polarization & majority unity in the U.S. Senate.

Figure 8:

Great polarization & majority unity in the U.S. Senate.

4.2 Lower Legislative Consideration & Committee Work in the Senate

As mentioned earlier, a key component of standard theories of legislative organization is delegation of agenda control powers from party members to party leaders (Cox and McCubbins 2005; Rohde 1991). According to Cox and McCubbins (2005), majority party leaders use this majority party control to provide a partisan record of accomplishments upon which their members seek re-election. The minority party seeks to halt these efforts on both ideological and electoral grounds. Relative to the House of Representatives, the U.S. Senate grants individual Senators and the minority party with greater procedural rights, such as the filibuster and the corresponding Rule 22 requiring a 60-vote supermajority in order to stop debate and vote on a legislative proposal (DiSalvo 2011; Koger 2011). Historically reserved for times when the “most intensely held interests were at stake” (Fenno 1989), the usage of the legislative filibuster is a consistent mainstay of the contemporary Senate (Binder 2011). As Binder (2011) articulates “sixty votes has become the de facto threshold for legislative agreement” in the contemporary Senate, with the exception of non-budgetary legislation subject to reconciliation (DiSalvo 2011) and all executive and judicial nominations (Oleszek et al. 2016).[16] Widely portrayed as an institution marred by gridlock and obstruction due to the prevalent use of the filibuster, scholars have quipped that the contemporary Senate suffers from the “Senate Syndrome.” Smith (2010) describes the contemporary Senate as one in which “each party assumes that the other party will fully exploit its procedural options” – the minority will be “quick to obstruct” and the majority will be “quick to restrict” opportunities for the minority to engage in the legislative process.

We should expect this “Senate Syndrome” to get worse as the Senate continues to polarize on ideological policy grounds and agenda setting powers centralize in majority party leadership. During periods of greater polarization, the minority should increasingly resort to filibusters to invoke a higher cost on the majority to pass its legislative agenda. The root causes of this obstruction will be ideological differences and electoral concerns — i.e. preventing the majority party from building a legislative record to use in re-elections (Cox and McCubbins 2005). As Koger (2011) notes, the mere threat of a filibuster in the contemporary Senate is tantamount to a veto by the minority on a majority legislative proposal. No actual filibustering is required. While this makes measuring obstruction difficult, given that the threats of filibustering may be conveyed to party leaders in private channels rather than in public (see Koger 2010, for a comprehensive way to measure obstruction in this context), the Senate majority may respond to the threat of a filibuster by filing a cloture petition designed to force a vote on the minority’s obstruction. 60-votes are then required to invoke cloture and put an end to the filibuster. While counting the number of cloture votes may under-count the prevalence of filibuster obstruction in the Senate (Oleszek et al. 2016, p. 276), counting cloture votes does provide a measure of procedural Senate obstruction.

Figure 9 gives strong evidence that as the Senate polarizes, the number of cloture votes and the proportion of the roll-call agenda consisting of cloture votes increases.[17] The U.S. Senate Cloture Counts data shown in Figure 9 begins in 1917, which was the year the Senate formally adopted Rule XXII providing for the cloture vote mechanism.[18] According to the U.S. Senate Cloture Counts data, the 116th Republican Senate saw a staggering 298 cloture votes on 328 cloture petitions filed, with 41% of all roll-call votes consisting of cloture votes, making the 116th Senate both the most polarized and marred in cloture votes since the start of the direct-election era in 1914. It is clear that the Senate has transformed from a deliberative, and ultimately final passage voting, institution to a “highly partisan” polarized legislative body marred in obstruction and gridlock (Binder 2011).

Figure 9: 
Great polarization & obstruction in the U.S. Senate.

Figure 9:

Great polarization & obstruction in the U.S. Senate.

As Smith (2010) articulates, one potential consequence of the “Senate Syndrome” defining the contemporary Senate is the majority party restricting the opportunities of the minority party to influence the legislative process. For example, the Senate majority leader may use the right of first recognition to fill the amendment tree with their own amendments, thus blocking consideration of any amendments offer by other Senators (see Chaturvedi 2018; Den Hartog and Monroe 2011, for a comprehensive treatment of this procedural tool). As a general matter, PCT posits that majority party leadership may seek to limit amendments considered on the floor and even forgo consideration of amendments on legislation considered salient to the majority party out of fear of creating a more costly legislative process by forcing more roll-call votes (Cox and McCubbins 2005). Indeed, during a fight over amendments on legislation regarding the manipulation of Chinese currency on October 6, 2011, Senate Majority Leader Harry Reid (D-NV) invoked a “nuclear option.” Senate rules were changed to prevent Republicans from forcing votes on potentially damaging amendments after invoking cloture, thus severely restricting the right of Senators to offer amendments on the floor and leaving Senate Minority Leader Mitch McConnell (R-KY) “fuming” (Binder 2011).[19] Within the context of the polarized Senate, the Senate majority leadership may seek to limit any deliberation of legislative amendments on the floor —in a similar manner as Senate Majority Leader Reid—in order to protect the electoral brand of their party by denying additional roll–call votes that could force their Senators into potentially damaging votes.[20] Figure 10 provides evidence that the number of amendments and the rate of amendments as a percentage of the roll-call agenda declines since the beginning of the data series in the 91st Congress in 1969 to the conclusion of the 116th Senate in 2021. Indeed, during the 115th and 116th Republican Senates, only 71 and 60 amendments respectively received roll-call votes, constituting only 12 and 8% of the roll-call agenda for each respective Congress. This lends support to the proposition that as the Senate polarizes, the Senate majority seeks to restrict the number of amendments considered on the floor (Binder 2011). This may not be surprising, given that majority party leaders are tasked with using negative agenda control to leave items off the agenda that may damage the partisan electoral brand, which as we show is pivotal in deciding electoral outcomes in the polarized era.

Figure 10: 
Great polarization & lower amendment consideration in the U.S. Senate.

Figure 10:

Great polarization & lower amendment consideration in the U.S. Senate.

The association of polarization and partisanship with greater obstruction and far lower consideration of legislative amendments points to a contemporary Senate plagued by a lack of deliberation in the policymaking process. Another way to assess deliberation in the policymaking process is within the context of Senate committees. Beginning with Wilson’s (1885) infamous observation that “Congress in its committee rooms is Congress at work,” scholars recognized that committees play an essential role in the division of labour within Congress. Each committee and its members are tasked with crafting and shepherding legislation falling under their jurisdictional policy property rights. In addition, committees play an essential role in providing Congress with the expertise and information necessary to draft legislation on complex problems. Members of committees specialize in specific policy domains and rely on outside witnesses to inform the policymaking process (see Krehbiel 1991). Traditionally, scholars have posit that committees, and the legislators that lead them, are relatively autonomous actors that use their jurisdictional policy property rights to push legislation to the full chamber that advances the electoral goals of all members on the committee (Mayhew 1974).[21] By contrast, the party-centered PCT argues that committees are merely extensions of party leadership, with the “senior partners” (i.e., Chairmen) tasked with leading these committees in lockstep with the desires of other party leaders, such as the House Speaker or Senate Majority Leader. Moreover, with greater centralization of power during periods of polarization, the crafting of legislation should move away from committees and towards informal centralized majority party leadership structures (Theriault 2008, Ch. 7).[22] In recent years, some Senators have bemoaned this shift from committees to centralized party leadership. Senator Lamar Alexander (R-TN) insisted on the first day of the 112nd Congress that the “real obstructionists have been the Democratic majority which for an unprecedented number of times, have used their majority advantage to limit debate, not allow amendments and bypass the normal committee consideration of legislation.”[23] Analogous to the previous finding of declining floor consideration of legislative amendments, we expect the observed workload of the Senate committees to decrease as the Senate becomes more polarized and as power becomes more centralized in majority party leadership.

Figure 11 shows that since 1946, more polarized Senates coincide with fewer hearings held by Senate committees and subcommittees. Beginning with the 113rd Senate (2013–2015), the number of committee hearings drops monotonically during the four most polarized Senates found in the 114th, 115th, and 116th Congresses. The 116th Congresses had only 154 committee hearings. To place this in context, the 106th Senate, in session from 1999 to 2001, held 1171 committee hearings, or 87% more hearings than those held in the 116th Senate. We argue that the decline of committee hearings during periods of high partisanship represents a loss of deliberative contribution from committees and a shift in power to majority party leadership.

Figure 11: 
Lower committee deliberation as the U.S. Senate polarizes.

Figure 11:

Lower committee deliberation as the U.S. Senate polarizes.

5 Discussion: The Contemporary Partisan & Obstructionist Senate

This paper demonstrates that the contemporary U.S. Senate is the most polarized since the end of the Civil War. This provides three key implications for the Senate. First, Senate elections are as partisan as House elections. Individual candidates are less significant electorally as partisan performance at the presidential and congressional level becomes largely congruent as Capitol Hill becomes polarized. Second, polarized Senates have both more unified and cohesive parties and smaller majorities. These smaller majorities are, likewise, more unified than in less polarized Senates. Finally, polarized Senates are more obstructionist and far less deliberative, as demonstrated by the increased proportion of cloture votes in roll call vote totals and the decreased number of committee hearings. Legislative power appears to move away from committees and becomes centralized in Senate leadership offices as the Senate polarizes. Each of these implications is demonstrated empirically using various analyses and measures.

We also witnessed the impact of partisanship on deliberation and productivity first-hand in our roles as American Political Science Association Congressional Fellows placed in the U.S. Senate during the 116th and 117th Congresses, respectively. A jolting experience for any Senate staffer is going to the floor of the Senate for the first time to listen to your boss give a speech to a mostly empty room. Indeed, this is the norm for most Senate speeches. Speeches are not intended to convince colleagues or promote deliberation about the common good. Typically, the only people watching are the viewers of C-SPAN, the very bored presiding Senate member, and the personal or committee staff sitting along the back wall. One of the most remarkable aspects of the second impeachment trial of former President Trump was the presence of the entire Senate in the chamber at the same time. This was extremely unusual. Of course, some votes will see most members of the Senate stand around in the chamber at roughly the same time. The impeachment trial was different. Senators were sitting and listening. Some were even swayed by the arguments presented for or against impeachment. The fact that this was so unusual in the contemporary Senate tells us that the floor of the Senate is not the location for deliberation today.

What about Senate committees? Historically, Senate committees have been powerful legislative bodies where deliberation on policy takes place. Yet, as this paper shows, committees are no longer the center of policymaking. The number of committee hearings decreases significantly as the Senate polarizes. Committee hearings are particularly striking for what does not occur. Questions to the witnesses are mostly speeches followed by a leading question. Almost none of the Senators engage with questions asked by other Senators. Where is deliberation to be found in the Senate?, In any case, much of the most significant legislation bypasses regular order entirely, meaning that it skips hearings and markups in committees. Perhaps, then, it is in friendship that deliberation and productivity are found. The bipartisan infrastructure package was crafted and passed on the foundation of compromise and trust between an evolving set of more or less moderate Senators. This would not have been possible without mutual trust and good faith compromise. Likewise, Senator Kirsten Gillibrand’s (D-NY) landmark legislation on sexual assault in the military gained widespread, bipartisan support only after her friendship with Senator Joni Ernst (R-IA) led to Ernst’s cosponsorship. Alas, these are the dying lights of friendship and trust in the Senate, both of which are difficult to keep alive in us-versus-them days. Gone are the days of Senators Ted Kennedy (D-MA) and Orrin Hatch’s (R-UT) odd friendship. The pressures of passionate political bases and three day work weeks make such relationships perilous. As a petty example, see the outraged reaction to Senator Mitt Romney’s (R-UT) and Senator Kyrsten Sinema’s (D-AZ) common themed Halloween costumes. Compromise is not rewarded in the days of hyper-partisanship.

Some pundits and political scientists have held forth the abolition of the filibuster as the Senate’s saving grace. Certainly, removing the filibuster would reduce the transaction costs required to pass policy by the Senate majority. While critics contend that remove of the filibuster would minimize the need for compromise, we note that transaction costs and compromise will still be integral to the policymaking process, even during periods of unified control of Congress. Indeed, due to the inherent nature of bicameralism and required intrachamber agreement required to pass policy, policymaking would still require agreement of differing legislative coalitions as Senators represent more heterogeneous statewide interests relative to their House colleagues which represent more homogeneous district interests. Simply put, compromise will still be a necessary condition for policymaking given institutional differences “to promote diverse ambitions” in House and Senate on the basis of constituency, length of term, and apportionment (Stone and McCann 2020, Ch. 1). Elimination of the filibuster would also remove the last symbolic barrier to partisan rancor in the Senate. The filibuster was, at its best, a procedure that could promote compromise and cross-party deliberation, a rule that set the United States Senate apart from the House of Representatives. At its worst, the filibuster has become an anti-democratic weapon of obstruction and partisanship. Nevertheless, we caution that removing the filibuster will not fix the partisanship and polarization that lead to decreased productivity and deliberation in the Senate. As we show, a polarized Senate is also associated with lower deliberation in committee and consideration of floor amendments, which we contend is congruent with prominent theories positing greater agenda control of the policymaking process by party leaders (Cox and McCubbins 2005), particularly during periods of greater polarization (Rohde 1991). We should not expect the removal of the filibuster to fix a polarized leader-driven Senate plagued by partisan conflict and a lack of deliberation.


Corresponding author: Carlos Algara, Department of Politics & Government, Claremont Graduate University, Claremont, CA, USA, E-mail:

Manuscript prepared for the January 2022 special volume on the United States Senate in The Forum: A Journal of Applied Research in Contemporary Politics.


Appendix

Figure 2A: 
The Increasing Explanatory Power of Partisanship in Congressional Election Outcomes.

Figure 2A:

The Increasing Explanatory Power of Partisanship in Congressional Election Outcomes.

Figure 3A: 
Lack of Deviation in Partisan Electoral Performance As Congress Polarizes.

Figure 3A:

Lack of Deviation in Partisan Electoral Performance As Congress Polarizes.

Figure 4A: 
Greater Congruence in Constituency & Legislator Partisanship as Congress Polarizes.

Figure 4A:

Greater Congruence in Constituency & Legislator Partisanship as Congress Polarizes.

Figure 5A: 
Shrinking Partisan Majorities As Congress Polarizes.

Figure 5A:

Shrinking Partisan Majorities As Congress Polarizes.

Figure 6A: 
Great Polarization & Partisan Votes in the U.S. Senate.

Figure 6A:

Great Polarization & Partisan Votes in the U.S. Senate.

Figure 7A: 
Great Polarization & Party Unity in the U.S. Senate.

Figure 7A:

Great Polarization & Party Unity in the U.S. Senate.

Figure 8A: 
Great Polarization & Majority Unity in the U.S. Senate.

Figure 8A:

Great Polarization & Majority Unity in the U.S. Senate.

Figure 9A: 
Great Polarization & Obstruction in the U.S. Senate.

Figure 9A:

Great Polarization & Obstruction in the U.S. Senate.

Figure 10A: 
Great Polarization & Lower Amendment Consideration in the U.S. Senate.

Figure 10A:

Great Polarization & Lower Amendment Consideration in the U.S. Senate.

Figure 11A: 
Lower Committee Deliberation as the U.S. Senate Polarizes.

Figure 11A:

Lower Committee Deliberation as the U.S. Senate Polarizes.

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Published Online: 2022-02-14

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