Polarization and US foreign policy: key debates and new findings

Abstract

Polarization in the USA has been on the rise for several decades. In this context, few observers expect politics today to stop “at the water’s edge,” as the old cliché goes. But key questions about the relationship between polarization and US foreign policy remain to be fully answered. To what extent are American ideas about foreign policy now polarized along partisan lines? How is polarization changing the foreign policy behavior of the US Congress and President? And how is polarization altering the effectiveness of US foreign policy and influencing America’s role in the world? In this introductory article to our special issue “Domestic Polarization and US Foreign Policy: Ideas, Institutions, and Policy Implications,” we provide an overview of key debates and existing knowledge about these questions, highlight important new findings from the contributions to the special issue, and suggest avenues for further research on this increasingly important topic.

Full text

Vol.:(0123456789)
International Politics (2022) 59:767–785
https://doi.org/10.1057/s41311-022-00381-0
ORIGINAL ARTICLE
Polarization andUS foreign policy: key debates andnew
findings
GordonM.Friedrichs1 · JordanTama2
Accepted: 1 February 2022 / Published online: 11 March 2022
© The Author(s) 2022
Abstract
Polarization in the USA has been on the rise for several decades. In this context,
few observers expect politics today to stop “at the water’s edge,” as the old cliché
goes. But key questions about the relationship between polarization and US foreign
policy remain to be fully answered. To what extent are American ideas about foreign
policy now polarized along partisan lines? How is polarization changing the foreign
policy behavior of the US Congress and President? And how is polarization altering
the effectiveness of US foreign policy and influencing America’s role in the world?
In this introductory article to our special issue “Domestic Polarization and US For-
eign Policy: Ideas, Institutions, and Policy Implications,” we provide an overview of
key debates and existing knowledge about these questions, highlight important new
findings from the contributions to the special issue, and suggest avenues for further
research on this increasingly important topic.
Keywords Polarization· US foreign policy· Public opinion· Congress·
Presidency· International order
Polarization has become a dominant phenomenon in contemporary American poli-
tics (McCarty etal. 2016; McCarty 2019). Partisan division, both among the pub-
lic and political elites, has consumed American democracy, transforming a politi-
cal system dependent on compromise into one suffused by hostility, gridlock, and
dysfunctional democratic governance (Binder 2015; Lee 2015). Partisans often view
supporters of the other party as essentially different, unpatriotic, and morally wrong,
which has fostered acts of mutual discrimination, divergent understandings of facts,
* Gordon M. Friedrichs
gordon.friedrichs@politik.uni-freiburg.de
Jordan Tama
tama@american.edu
1 University ofFreiburg, Freiburg, Germany
2 American University, WashingtonD.C., USA
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G.M.Friedrichs, J.Tama
justifications for antidemocratic behavior, and even outright hate (Finkel etal. 2020).
These trends have only become more pronounced with the rise of populism and
growing threats of violence against elected officials (Howell and Moe 2020; Itkowitz
and DeBonis 2021).
The term polarization is routinely used in a variety of ways, underscoring the
importance of defining the term clearly and distinguishing among types or dimen-
sions of polarization. Broadly, polarization refers to a state in which the opinions,
feelings, behaviors, or interests of a group or society become more bimodal and
the two modes move further apart.1 This broad concept can be broken down into
more specific types of polarization. Ideological or preference polarization refers to
the polarization of people’s views about public issues, either across-the-board or in
particular policy areas (Noel 2013; Carmines and D’Amico 2015; McCarty et al.
2016; Kertzer etal. 2021). Affective polarization, or negative partisanship, refers to
sharpening feelings of animosity between people of different political persuasions
(Abramowitz and Webster 2016; Mason 2018; Iyengar etal., 2019). Some work also
points to the importance of residential or social polarization, characterized by peo-
ple becoming increasingly separated into communities or groups that interact with
each other less (Nall 2015; Alduncin etal. 2017). When any type of polarization
overlaps with party identities, partisan polarization exists. Partisan polarization can
also be fueled by partisan warfare—the no-holds-barred approach in which politi-
cians seek above all to expand the power of their own party and weaken the other
party (Lee 2009; Jacobson 2013; Theriault 2013).
Scholars of American politics have studied the causes and consequences of
polarization (Theriault 2008; Persily 2015; Campbell 2016; Thurber and Yoshinaka,
2015; Klein 2020). Various studies suggest that polarization leads to political grid-
lock and obstructionism, a decline in policy innovation and progress, and even a
drop in public support for democracy (Hetherington and Weiler 2009; Binder 2015;
Lee 2015; Barber and McCarty 2016; Gerber and Schickler 2017; Svolik 2019). Yet
while the polarization of US politics and society has been a prevalent phenomenon
of American democracy since the 1970s, key questions about the scope, character,
and implications of polarization in US foreign policy remain to be fully answered.
In recent years, the subject has begun to receive increased attention from inter-
national relations scholars and US foreign policy analysts (Walt 2019). One body
of work has examined the extent to which polarization in US foreign policy is on
the rise. The chief finding in these studies, which have focused mainly on congres-
sional behavior or public attitudes, is that Democrats and Republicans have grown
further apart on international issues, just as they have on domestic matters (DeLaet
and Scott 2006; Kupchan and Trubowitz 2007; Snyder et al. 2009; Trubowitz and
Mellow 2011; Peake etal. 2012; Gries 2014; Schultz 2017; Jeong and Quirk 2019;
Smeltz etal. 2020). Related research shows how increased polarization is weaken-
ing the capacity of Congress to shape foreign policy or oversee the executive branch
(Fowler 2015; Goldgeier and Saunders 2018). But other work has pointed to contin-
uing areas of agreement or overlap between Democrats and Republicans, or ongoing
1 This definition draws on Lee 2015, 263.
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Polarization andUS foreign policy: key debates andnew findings
congressional influence, on foreign policy (Chaudoin etal. 2010; Scott and Carter
2014; Busby etal. 2020; Tama 2020; Kertzer etal. 2021). Given these contrasting
findings, more research is needed to fully understand the degree to which contem-
porary foreign policy debates are polarized, variation in political dynamics across
areas of foreign policy, and the relationship between polarization and the behavior
of policy making institutions.
Some scholars have also explored how foreign policy polarization can affect the
outward-facing content or effectiveness of US foreign policy. The principal con-
cern of this work is that polarization undermines bipartisan consensus for the grand
strategy of liberal internationalism that often guided US foreign policy in the post-
World War II era (Kupchan and Trubowitz 2007; Jervis et al. 2018). In the words
of Peter Trubowitz and Peter Harris, hyper-partisanship, the absence of a compel-
ling foreign policy narrative, and the erosion of the domestic social contract have
weakened America’s “domestic political capacity to translate […] power assets into
international influence” (Trubowitz and Harris 2019: 621). In a similar vein, Daniel
Drezner writes that the “American foundations undergirding the liberal international
order are in grave danger” (Drezner 2019: 10).2 Kenneth Schultz has highlighted
additional effects of polarization, explaining how it makes US foreign policy less
reliable, less capable of learning from past mistakes, and more vulnerable to harm-
ful external influences (Schultz 2017). In a 2018 survey, US foreign policy profes-
sionals even ranked domestic polarization as the most critical threat to the USA
(Smeltz etal. 2018). But some work points to the resilience of US support for liberal
internationalism, highlighting ways in which domestic institutions and international
realities constrain nationalist leaders from fully institutionalizing “America First”
policies, and explaining why US leaders will continue to have incentives to pursue
internationalist policies in an interconnected world (Chaudoin et al. 2018, 2021;
Ikenberry 2020).
While these and other studies have provided a rich set of insights about the rela-
tionship between polarization and the content of US foreign policy, scholars have
only begun to examine the impact of foreign policy polarization empirically. Moreo-
ver, the effects of polarization in particular foreign policy domains, such as interna-
tional negotiations or military operations, are largely unexplored. With the existence
and strength of a liberal international order being contingent in part on sustained US
engagement, it is important to better understand the repercussions of polarization for
America’s international commitment. The need for more research on these topics is
only enhanced by the legacy left by Donald Trump, whose nationalist agenda and
particularly partisan approach to politics presented especially strong challenges both
to remaining reservoirs of bipartisanship and to key mechanisms of international
cooperation (Jacobson 2017; Jervis etal. 2018; Stokes 2018).
With that context in mind, this special issue sets out to answer the following main
questions: To what extent are US foreign policy debates polarized along partisan
2 Other scholars highlight limits in the extent of bipartisan foreign policy consensus or in the scope of
the liberal international order even during the Cold War (Rathbun 2012, Acharya 2018, Allison 2018; see
also McCormick and Wittkofpf 1990; Meernik 1993).
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G.M.Friedrichs, J.Tama
lines? How is polarization affecting the institutions of US foreign policy? And how
is polarization changing the conduct or effectiveness of US foreign policy? In this
overview article, we review new findings on these questions from articles in this
special issue, situate those findings within prior scholarship on polarization and for-
eign policy, and suggest avenues for additional research that could further advance
the frontier of knowledge in this area.
Overall takeaways
The articles in this special issue present new research on the polarization of for-
eign policy ideas, the relationship between polarization and foreign policy institu-
tions, and the effects of polarization on the conduct of US foreign policy. The arti-
cles cover an array of substantive issue areas, including military intervention, arms
control, foreign policy spending, trade, and America’s international reputation. They
also draw on many types of data, from conventional public opinion polls, to survey
experiments, to information on a wide array of congressional activity. Moreover, the
articles employ a variety of analytical methods, including statistical analyses, quali-
tative comparative analysis, and case studies. Collectively, the authors provide the
most comprehensive look to date at the nature, extent, and implications of polariza-
tion on US foreign policymaking and execution.
The articles show how different types of polarization are manifested in contem-
porary US foreign policy, in both public attitudes and in the behavior of elected
officials. On the extent of polarization, they illustrate the prevalence of ideologi-
cal, social, and partisan divisions on foreign policy in recent years, but also sug-
gest the need to incorporate some nuance into claims about polarization. Debates on
issues ranging from climate change and immigration (Smeltz 2022), to arms control
(Böller 2022), to the conduct of war (Lee 2022), to foreign policy spending (Bendix
and Jeong 2022) reveal large and/or growing gaps between the preferences of Demo-
crats or liberals, on the one hand, and Republicans or conservatives, on the other.
Even views on some issues that previously exhibited little partisan divergence, such
as attitudes toward China, Russia, and the Israel-Palestinian conflict, have recently
become more polarized (Smeltz 2022). Members of Congress are also traveling
abroad with lawmakers from the other party less often, reflecting a weakening social
fabric on Capitol Hill (McGee and Theriault 2022).
At the same time, it remains surprisingly common for Democratic and Republi-
can lawmakers to vote together on foreign policy (Bryan and Tama 2022), and presi-
dents retain the capacity to achieve bipartisan support for certain kinds of military
intervention (Maxey 2022). Moreover, on some issues, such as international trade
and the scope of executive power, divisions within the parties or between Congress
and the executive are at least as salient as divisions between liberals and conserva-
tives (Bryan and Tama 2022; Friedrichs 2022; Homan and Lantis 2022). The upshot
is that preference polarization is intensifying in many respects, but not uniformly
and not to the exclusion of other political dynamics.
The articles also provide new insights and data on the effects of polarization on
the institutions, execution, and effectiveness of US foreign policy. By making it
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Polarization andUS foreign policy: key debates andnew findings
more difficult for lawmakers to build the broad coalitions that are typically needed
to enact laws, polarization is weakening congressional influence and enabling a fur-
ther expansion in executive power, potentially facilitating rash or unwise presidential
foreign policy actions (Marshall and Haney 2022). While lawmakers have sought
to maintain congressional influence by shifting legislative activity to limitation rid-
ers—amendments to appropriations bills that restrict or prohibit certain types of
spending—such devices are not well-suited to all types of foreign policy measures
(Carcelli 2022).
Polarization also shapes and limits decisions on military action and international
cooperation. Since Democrats place greater value than Republicans on avoiding
civilian casualties and accord less importance than Republicans to achieving mili-
tary victories, Democratic leaders tend to be more cautious with regard to the use
of force than their Republican counterparts (Lee 2022). With regard to international
cooperation, US presidents are becoming less capable of achieving Senate approval
of international agreements as the prevailing ideology of Republican elected offi-
cials becomes more conservative (Böller 2022). At the same time, rising US prefer-
ence polarization is weakening overseas confidence in America and reducing the
willingness of citizens abroad to cooperate with the USA (Myrick 2022).
A few of the articles point to some more optimistic takeaways. The increased use
by Congress of spending restrictions shows that lawmakers can adapt to political
constraints in ways that enable them to maintain policy influence (Carcelli 2022).
The role of ideology as a driver of congressional behavior can also enable Congress
to act as a source of policy innovation (Bendix and Jeong 2022), while the intraparty
divisions that characterize some foreign policy debates can foster the emergence
of new ideas, policy entrepreneurs, and cross-cutting coalitions (Friedrichs 2022;
Homan and Lantis 2022). Overall, though, the authors provide a variety of impor-
tant cautionary tales about ways in which polarization can make it more difficult to
carry out an effective foreign policy.
Polarization andforeign policy ideas
A large literature has documented important differences between how liberals
and conservatives view the world. Whereas liberals favor a cooperative approach
to international politics and prefer non-military to military instruments of national
power, conservatives are warier of multilateral mechanisms and more supportive
of military might (Wittkopf 1990; Holsti 2004; Broz 2011; Rathbun 2012; Gries
2014; Milner and Tingley 2015; Jeong and Quirk 2019; Wenzelburger and Böller
2019; Raunio and Wagner 2020; Smeltz etal. 2020; Flynn and Fordham 2021). At
the same time, US debates over some foreign policy issues, including international
alliances, economic sanctions, humanitarian intervention, and human rights, do not
break down consistently along left–right lines (Cutrone and Fordham 2010; Maxey,
2020; Busby etal. 2020; Tama 2020; Kertzer etal. 2021). In addition, many issues,
such as international trade and foreign aid, involve both interparty and intraparty
divisions (Thérien and Nöel 2000; Milner and Judkins 2004; Milner and Tingley
2010; Prather 2016; Rathbun 2016). In short, liberals and conservatives are strongly
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G.M.Friedrichs, J.Tama
polarized on some major foreign policy questions, but the overall alignment between
left–right ideology and foreign policy preferences is highly imperfect.
Prior work has also explored the relationship between public attitudes and the
views of decision-makers or elites. On the one hand, scholars have established that
citizens have certain core values that shape their worldviews, suggesting that the
public forms some of their own judgments about international issues (Rathbun etal.
2016; Kertzer and Zeitzoff 2017). Public attitudes, in turn, sometimes influence
the decision-making of leaders, particularly on salient issues (Aldrich etal. 2006;
Foyle 2017). On the other hand, studies have shown that cues from leaders and other
elites can themselves greatly shape public attitudes on foreign policy (Zaller 1992;
Berinsky 2009; Guisinger and Saunders 2017). One consequence of this elite cue
dynamic is that polarization among elites tends to filter down and exacerbate ideo-
logical polarization among the public (cf. Westwood 2019).
Given these interrelationships, it is important to understand how and to what
extent foreign policy ideas are polarized among the public and decision-makers.
Several of the articles in this special issue evaluate whether, to what extent, and how
the views of citizens or leaders about US foreign policy are becoming polarized
along left–right or other lines.
Dina Smeltz examines preference polarization in public attitudes on foreign pol-
icy, drawing on a long-running series of surveys conducted by the Chicago Council
on Global Affairs (Smeltz 2022). She finds that polarization in public foreign policy
views is increasing overall, but some issues are far more polarized than others. Dem-
ocrats and Republicans still largely agree on the big-picture framework and goals
of US foreign policy, supporting active engagement in the world, security alliances,
overseas military bases, and international trade. Consistent with long-standing
liberal-conservative divisions, polarization is much greater on some key means of
foreign policy, such as the importance of multilateral institutions and military supe-
riority. Most strikingly, polarization with respect to threat perceptions has jumped
in recent years, with Republicans more concerned about hard security threats, such
as the rise of China and international terrorism, and Democrats more concerned
about the COVID-19 pandemic, climate change, and racial and economic inequal-
ity at home. These differences reveal that Democrats and Republicans do not even
agree about which types of issues should demand government attention. Smeltz also
discusses how presidential messaging on some hot-button issues, particularly under
Donald Trump, has exacerbated polarization.
Sarah Maxey tackles another dimension of public attitudes, using original sur-
vey experiments to explore the influence of affective polarization on the American
public’s support for military intervention (Maxey 2022). She finds that the impact
of affective polarization on public support for military action varies across types
of intervention and between Democrats and Republicans. Whereas affective polar-
ization makes it harder for presidents to gain bipartisan support for interventions
motivated by security goals, it does not limit the ability of presidents to achieve
bipartisan backing for humanitarian interventions. In another important nuance,
Democratic and Republican leaders face different political landscapes on the use of
force, as the greater support of Republican citizens for military action makes it is
easier for Democratic presidents than for Republican presidents to gain bipartisan
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Polarization andUS foreign policy: key debates andnew findings
support when deploying the military into combat. The upshot is that debates over
the use of force are not immune to polarizing dynamics, but there exist important
distinctions in the politics of military intervention debates.
William Bendix and Gyung-Ho Jeong consider the attitudes of elected officials,
investigating the relative importance of ideological preferences and partisan cal-
culations as drivers of congressional decision-making on amendments concerning
defense and foreign aid spending (Bendix and Jeong 2022). Whereas much research
on congressional decision-making focuses solely on the voting behavior of law-
makers, Bendix and Jeong evaluate contributors to both legislative cosponsorship
and legislative votes. They find that ideological preferences strongly influence both
cosponsorship and voting decisions, with liberals favoring amendments that limit
defense spending and conservatives favoring amendments that limit foreign aid.
While party identities also influence voting patterns on these limitation riders, ideo-
logical preferences play a more important role. More broadly, their study suggests
that liberal and conservative ideologies greatly shape how members of Congress
approach foreign policy issues.
Patrick Homan and Jeffrey Lantis offer a different take on congressional foreign
policy views, highlighting the importance of establishment and anti-establishment
factions within each party in debates over war powers (Homan and Lantis 2022).
While most studies of congressional views hone in on the roles of liberal and con-
servative ideology, Homan and Lantis underscore differences in the attitudes of leg-
islators regarding the exercise of power in Washington. Based on an examination
of congressional votes concerning the use of force during the Obama and Trump
administrations, they find that progressives and conservatives possessing anti-estab-
lishment views often split from their party leaders and align with each other in seek-
ing to restrict the authority of the executive branch to deploy the military overseas.
Even when such intraparty factions are relatively small, they have the potential to
shape legislative outcomes when Congress is closely divided between the two par-
ties, as it has typically been in recent years.
Polarization andforeign policy institutions
The polarization of American politics and society severely challenges the demo-
cratic accountability of the political system and its agents, while changing how
elected representatives carry out their roles and responsibilities (Sinclair 2016; Cay-
ton and Dawkins 2020; Page and Gilens 2020). A key observation by scholars is that
the alignment of political ideologies and partisanship has led to partisan conflict in
Congress with the goal to prevent political achievements of the opposition (The-
riault 2013; Hetherington and Rudolph 2015). Recent polling shows that the most
salient reason why Americans identify with a political party—besides their party’s
policies—is the conception that the other party will do harm to the country (Pew
Research Center 2018). At the same time, partisan warfare has been exacerbated by
the small size of congressional majorities and frequent turnover of party control on
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G.M.Friedrichs, J.Tama
Capitol Hill in recent years, which provides parties with a greater incentive to focus
on partisan competition (Lee 2016).
As a result of these trends, both parties have instituted procedural changes in
order to increase their political success rate, including strengthening the party lead-
ership to expedite partisan legislation and relying less on the seniority system when
naming committee chairs (Cox and McCubbins 2005; Evans 2012; Wallner 2013;
Smith 2014). The majority party has sought to suppress minority opposition to push
through its policy agenda via the use of restricted and closed rules to prevent floor
amendments to a bill as well as budget resolutions and reconciliation bills to avoid
filibuster threats (Baumer and Gold 2010; Binder 2018). In contrast, the minority
party increasingly relies on filibuster threats as well as on private actors and courts
to implement legislative statutes (Binder and Maltzman 2009; Fukuyama 2014:
10ff.).
Partisan conflict has also become visible in the foreign policy realm, during the
procedural and substantive foreign policy processes within Congress as well as in
the relationship between Congress and the president (Auerswald 2006; Auerswald
and Campbell 2012; Carter and Scott 2021). Some studies have shown a decline in
the presidential use of international treaties due to the growing difficulty of mar-
shaling bipartisan ratification majorities in Congress (DeLaet and Scott 2006; Peake
etal. 2012; Buys 2017). Scholars have also demonstrated that congressional action
on use of force questions is heavily shaped by partisan goals (Howell and Pevehouse
2007; Brulé 2008; Kriner 2010). Others find more generally that partisan conflict
weakens the legislative branch’s role as check and balancer of the executive branch
(Mann and Ornstein 2012; Fowler 2015; Franklin and Fix 2016; Goldgeier and
Saunders 2018; Friedrichs 2021). Another body of work has shown how polariza-
tion has bred a new generation of congressional foreign policy entrepreneurs, who
aim to change US foreign policy as well as their parties’ foreign policy position
(Marsh and Lantis 2016; Homan and Lantis 2020). In response to congressional
polarization, presidents increasingly circumvent a gridlocked legislative branch by
exercising executive power unilaterally (see Rudalevige 2005; Hendrickson 2015;
Edelson 2016; Burns, 2019). Partisan polarization also influences executive branch
appointments, leading presidents to appoint fewer officials from the opposition party
to senior positions (Flynn 2014).
Several articles in the special issue take a closer look at changes to the institu-
tions involved in US foreign policymaking due to polarization. Combined, they add
to our understanding of Congress’ role and presidential power in contemporary US
foreign policymaking.
Bryan Marshall and Patrick Haney assess changes to the role of Congress in the
foreign policy realm against the background of public expectations for strong US
global leadership (Marshall and Haney 2022). Through analyses of congressional
behavior such as voting, lawmaking, and oversight, they show that partisan polari-
zation has led to a decline in congressional power in foreign affairs. They find evi-
dence of partisan incentives for congressional abdication to the executive branch in
a decline in the number of foreign policy laws enacted by Congress, fewer checks on
presidential positions by congressional foreign policy committees, a weakening of
Congress’ power of the purse, and a growing tendency for presidential unilateralism.
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Polarization andUS foreign policy: key debates andnew findings
Overall, Marshall and Haney warn that these developments have created a serious
imbalance in the institutional authority of Congress and the president to execute
US foreign policy, and that this imbalance has the potential to jeopardize American
democracy.
James Bryan and Jordan Tama examine the frequency and character of congres-
sional bipartisanship on international issues compared to domestic ones (Bryan
and Tama 2022). Analyzing an original data set of nearly 3000 important congres-
sional votes since the end of the Cold War, Bryan and Tama find that severe cases
of polarization, in which more than 90 percent of the members of the two parties
vote on opposite sides, remain the exception in US foreign policy debates. In addi-
tion, they find that, overall, Congress is less polarized on international issues than on
domestic issues. By distinguishing among different forms of foreign policy bipar-
tisanship—pro-presidential, anti-presidential, and cross-partisanship—they provide
a more nuanced conception of the relationship between partisan polarization and
bipartisanship rates in Congress. While pro-presidential bipartisanship characterizes
most foreign policy votes, anti-presidential bipartisanship occurs strikingly often as
well. Moreover, Bryan and Tama find that bipartisanship rates vary across policy
domains, with international security issues enjoying more bipartisan consensus than
international economic issues. Overall, their findings suggest that despite increasing
ideological distance between members of both parties, Congress remains capable of
addressing international issues and enacting its constitutional role as check and bal-
ancer of the executive branch.
Shannon Carcelli argues that polarization and gridlock in Congress have incentiv-
ized legislators to turn to unorthodox foreign policymaking, particularly on foreign
aid policy (Carcelli 2022). Through the use of limitation riders (specifications writ-
ten within an appropriations bill that limit the administration’s policy discretion),
members of Congress seek to limit the allocation of aid to other countries or prevent
spending foreign aid money for particular purposes. Carcelli shows that through the
shift from more traditional means of foreign policy legislating to the increased use
of appropriations bills to shape foreign policy, Congress has been quite assertive
and influential despite high levels of partisan polarization. Quantitatively, she finds
evidence for an increase in the use of foreign aid limitation riders as polarization
increases. Qualitatively, she shows how the content of limitation riders is stronger
in high-polarization eras, as the topics of riders shift from budgets and contracting
issues to more substantive specifications regarding recipient countries and types of
aid. In addition, her findings indicate that an increase in congressional conserva-
tism decreases the use of limitation riders, suggesting that liberal majorities struggle
more to authorize foreign aid by traditional means.
Zachary McGee and Sean Theriault investigate the causes and consequences of
partisanship in congressional travels abroad (McGee and Theriault 2022). They
observe that congressional travels abroad have historically facilitated cordiality and
civility in Congress, as well as motivated legislators to reach across the aisle to foster
bipartisan consensus. Their analysis of overseas trips, known as Congressional Del-
egations (CODELS), from 1977 to 2018 reveals that Democrats with ideologically
extreme views travel abroad more often only with co-partisans, and that both Demo-
crats and Republicans with ideologically extreme views engage in fewer bipartisan
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G.M.Friedrichs, J.Tama
trips abroad. Combined, their results suggest that ideological extremism and partisan
warfare are shaping not only the voting behavior, but also the social interactions, of
members of Congress. This increased social polarization, in a vicious cycle, threat-
ens in turn to exacerbate polarization in the legislative process: just as party polari-
zation decreases the opportunity for members of Congress to develop personal rela-
tionships with each other, the lack of strong personal relationships across the aisle
makes it more difficult for members of Congress to craft bipartisan legislation later.
Polarization andforeign policy eectiveness
Domestic polarization not only affects the policymaking process but also the way
policies become implemented. Scholars of US foreign policy have shown that over
time, the highly contentious forces of domestic politics in some policy areas, such
as international economics, have incentivized the president to rely more heavily on
other instruments, such as military deployments and defense procurement (Milner
and Tingley 2015). Others have shown that partisan incentives have reduced presi-
dents’ use of force abroad and influenced how presidents carry out military opera-
tions (Howell and Pevehouse, 2007; Kriner 2010). Meanwhile, others have found
that greater prospects for legislative success incline the president to engage in more
high-risk military interventions and fewer humanitarian interventions (Marshall and
Prins 2016). In addition, studies on presidential use of executive agreements suggest
that domestic polarization inclines presidents to advance their agenda unilaterally
(Caruson and Farrar-Myers 2007; Amirfar and Singh 2018).
Polarization also influences the effectiveness of US foreign policy execution. As
some scholars have argued, polarization has limited the rally-around-the-flag effect
in response to external security threats (Myrick 2021). In addition, political and
material costs for the execution of certain partisan foreign policies and visions of
international order have increased in times of domestic polarization (Bafumi and
Parent 2012; Kreps etal. 2018). As a consequence of the widening gap domestically
for a cohesive strategy, the executive branch is more incentivized to politicize US
foreign policy through wedge-issues to weaken political opposition (Snyder et al.
2009). This, in turn, has contributed to a polarization of US relationships with allies
and partners (Drezner 2018).
Several articles in the special issue trace the consequences of domestic polariza-
tion for the conduct and effectiveness of US foreign policy. These articles tackle
the larger question of whether and how polarization undermines America’s global
power and standing across a range of issue areas.
Florian Böller analyzes the conditions under which the US role in arms control
policy has shifted from a “booster” that initiates new agreements, to a “brakeman”
that restricts or puts a halt to them (Böller 2022). Arms control treaties have been a
key element of the liberal international order under US global leadership and have
contributed to global security and disarmament. Via a crisp-set Qualitative Com-
parative Analysis, he evaluates 24 cases of US decisions on international arms
control treaties from 1963 to 2021, followed by a brief case study of the Trump
administration’s withdrawal from several agreements. Böller finds that the strength
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Polarization andUS foreign policy: key debates andnew findings
of conservative treaty skeptics in the US Senate contributed to the demise of arms
control policies since the end of the Cold War. In turn, the president’s party affili-
ation appears to be less decisive for the US role, although Democratic presidents
are more likely to support a booster role. In addition, the perceived reciprocity, or
“tit for tat,” embedded in the treaty, is an important condition that shapes US treaty
behavior. Overall, the ideology of senators, particularly their skepticism toward mul-
tilateral commitments, places a key structural constraint on US international treaty
making. As a result, Böller argues, changes in the presidency, from Trump to Biden,
for example, are insufficient to transform US arms control policy.
Gordon Friedrichs examines the extent and impact of intraparty polarization
in Congress on US trade policy (Friedrichs 2022). Facilitating trade liberalization
through multilateral organizations and free trade agreements has been characteristic
of US global leadership and the liberal international order since the end of World
War II. By relying on a new dataset of congressional letters and cosponsorship alli-
ances, Friedrichs derives trade policy preferences from members of Congress and
their ideological dispositions. Via a structured-focused comparison of two cases of
US trade policy—the Trans-Pacific Partnership Agreement and the US-Mexico-
Canada-Agreement—he shows that both parties are intrinsically polarized between
free and fair trade preferences. However, the relative strength of ideological factions
within both parties determines when legislators can build cross-cutting coalitions
in support of trade agreements. In addition, both case studies reveal that intraparty
preference polarization incentivizes the executive branch to pursue side-payments
and issue linkage in international trade negotiations, in an effort to forge cross-party
ratification majorities. Overall, these findings indicate that interparty polarization
induces intraparty polarization and bears the potential to generate foreign policy
realignments.
Carrie Lee investigates how polarization impacts presidents’ decisions to use
force abroad (Lee 2022). Lee argues that liberals and conservatives interpret war-
time casualties very differently from each other, which has significant implications
for public support for war and presidential decisions regarding military intervention.
Using three survey experiments, she assesses how ideology and party influence cas-
ualty sensitivity. Her findings reveal that conservatives are less likely than liberals
to change their support for military operations in response to increases in casual-
ties. This pattern holds under both Democratic and Republican presidents, suggest-
ing that ideology rather than partisanship is the key driver of it. Lee’s results suggest
that Republican presidents have strong incentives to pursue gains on the battlefield,
while Democratic presidents have strong incentives to limit the number of US casu-
alties. With polarization steadily increasing, ideological differences in the public’s
perception of warfare will likely translate into wide swings in military strategy from
administration to administration, undermining international trust in US security
leadership.
Rachel Myrick examines how partisan polarization affects British perceptions of
US security commitments and global leadership (Myrick 2022). The US–UK spe-
cial relationship has been considered a pillar of the liberal international order and
one that has proven particularly resilient despite various crises. Based on a survey
experiment involving 2000 adults in the United Kingdom, Myrick demonstrates how
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778
G.M.Friedrichs, J.Tama
US domestic polarization negatively impacts British citizens’ perception of the bilat-
eral relationship. She shows how foreign perceptions of extreme US polarization
weaken British willingness to engage in future partnerships with the US because
of an erosion of a bipartisan commitment to liberal norms, multilateralism, and an
open world economy. Furthermore, her findings reveal that polarization in the US
increases skepticism of American global leadership due to anticipation that US for-
eign policy will be more likely to change with executive turnover and thus be less
predictable. She further highlights that these negative reputational consequences due
to polarization are primarily driven by preference polarization between Republicans
and Democrats, rather than by affective polarization. Myrick’s findings contribute
to our understanding of some of the broader international consequences of domestic
polarization, particularly in increasing uncertainty around future US foreign policy.
Avenues forfurther research
Collectively, the articles in this special issue underscore both the progress that has
been made in the study of polarization and US foreign policy and the fertile ground
that exists for further research in this area. The answers to some questions related to
polarization and foreign policy are clear from these and other studies. On the whole,
foreign policy has not been immune from the rising levels of preference, affective,
social, and partisan polarization that have characterized American politics in recent
decades. From the public to members of Congress, Democrats and Republicans have
diverged in their views and behavior on international issues. This rising polariza-
tion has had a series of concerning effects, from an increase in US unilateralism to
a decline in America’s international cooperation capacity and overseas reputation.
At a time when a variety of policy challenges call out for enhanced international
engagement and cooperation, polarization is making it harder for the US to contrib-
ute constructively to global problem-solving and international order maintenance.
Yet some key debates about polarization and foreign policy remain unresolved.
While it is clear that the foreign policy views and behavior of Democrats and
Republicans have diverged, scholars differ in their assessment of the extent to which
members of each party have become ideologically homogenous. While some of the
studies in the special issue highlight the separation of Democrats and Republicans
into ideologically distinct camps on foreign policy (Bendix and Jeong 2022; Böller
2022), others highlight persistent intraparty divisions on international issues (Frie-
drichs 2022; Homan and Lantis 2022). More research is needed to further enhance
understanding of the relative importance of interparty polarization and intraparty
divisions. Further studies could also shed light on the specific alignment of differ-
ent types of polarization (ideological, affective, social, partisan) across and within
foreign policy areas. Given existing comprehensive work on the causes and driv-
ers of polarization in the domestic context, additional work on the extent to which
the repercussions of US global interdependencies and costly public goods provisions
have become themselves drivers of partisan or ideological polarization could be par-
ticularly promising (cf. Colgan and Keohane 2017; Norrlöf 2018). Such work should
be particularly timely in the wake of Donald Trump’s presidency considering the
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779
Polarization andUS foreign policy: key debates andnew findings
ways in which some of his foreign policy positions—for instance, on trade and the
US overseas military presence—diverged from Republican orthodoxy.
Further research is also needed to bolster understanding of the extent to which
Congress is still able to constrain the president in this highly polarized era. Overall,
articles in the special issue show that polarization is weakening Congress on foreign
policy, in areas ranging from legislating, to oversight, to overseas travel (Haney and
Marshall 2022; McGee and Theriault 2022). Yet Congress continues to challenge or
restrain the president on some important international issues, suggesting that there
remain substantial limits on presidential power (Bryan and Tama 2022; Carcelli
2022). One way to move this debate forward would be to trace the motivations of
legislators in seeking to manipulate the foreign policymaking process—for instance,
examining when legislators act to advance their own policy views and when they
act based on partisan goals. This would enhance understanding of the conditions
that facilitate bipartisan rather than partisan congressional opposition to presiden-
tial policies. Another way to advance this debate would be to shift some attention
from congressional behavior to presidential decision-making, using process-tracing
or other qualitative methods to examine the extent to which the president and other
executive branch officials take into account congressional views and positions when
making important foreign policy decisions.
New studies could also further investigate the effects of US polarization on the
behavior of other countries and the stability of international order. To date, most
work on the foreign policy effects of polarization, including several of the special
issue papers, has focused on how polarization can alter policy making dynamics in
Washington or change the international conduct of the USA (Schultz 2017; Böller
2022; Friedrichs 2022; Lee 2022). This body of work presents important findings
on the reliability of American democracy and US capacity to provide global public
goods in the light of domestic division, populism, and institutional corrosion (cf.
Daalder and Lindsay 2018; Diamond 2019; Musgrave 2019; Norrlöf 2020). Myrick
takes this research agenda a step further by investigating the effects of polarization
on overseas attitudes toward the USA (Myrick 2022). An implication of her paper
is that if overseas attitudes change, the behavior of foreign governments will also
likely change. But to what extent are foreign governments actually acting differ-
ently—for instance, by pursuing alternatives to partnerships with the US—based on
concern that they can no longer rely on US leadership or commitments? Moreover,
to what extent and when do US adversaries try to take advantage of weaknesses of
US foreign policy caused by domestic polarization? More broadly, to what extent is
increased domestic polarization contributing to changes in the formal and informal
architecture of the international order? These may be among the most important and
fruitful avenues for new research and they are particularly relevant against the back-
ground of established insights that democracies are reliable cooperation partners and
formidable in military warfare (Lake 1992; Bueno de Mesquita etal. 1999; Doyle
2005).
Finally, it would be worthwhile for scholars of foreign policy to build more con-
nections between research on US polarization and work on polarization in other
political contexts. To a large extent, scholarship on the politics of US foreign policy
has been conducted in isolation from scholarship on the politics of foreign policy in
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780
G.M.Friedrichs, J.Tama
other countries (cf. Somer & McCoy 2018; Carothers 2019). But some recent work
highlights important commonalities in party politics on foreign policy across con-
temporary democracies, underscoring the value of integrating knowledge about the
US case with knowledge about other cases (Wagner etal. 2017; Oktay 2018; Haese-
brouck and Mello 2020; Raunio and Wagner 2020; Wagner 2020; see also Beasley
etal. 2013). While some characteristics of American politics, such as its two-party
system, presidential democracy, electoral college system, and tradition of exception-
alism, mean that neither polarization dynamics nor the content of foreign policy will
ever be identical in the US and other democracies, we should strive to enhance our
understanding of similarities and differences in the extent, drivers, and effects of
polarization in countries across the globe.
Funding Open Access funding enabled and organized by Projekt DEAL.
Declarations
Conflict of interest On behalf of all authors, the corresponding author states that there is no conflict of
interest.
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License,
which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as
you give appropriate credit to the original author(s) and the source, provide a link to the Creative Com-
mons licence, and indicate if changes were made. The images or other third party material in this article
are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the
material. If material is not included in the article’s Creative Commons licence and your intended use is
not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission
directly from the copyright holder. To view a copy of this licence, visit http:// creat iveco mmons. org/ licen
ses/ by/4. 0/.
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