The Policy Consequences of Partisan Polarization in the United States
Nolan McCarty
Princeton University
The following is a very rough sketch of the argument and evidence for a book chapter in
preparation on the effects of partisan polarization on a number of facets of the policy
process in the United States.
In order prevent the “mischief of faction,” the founders designed a system of institutional
politics that preserves the status quo absent broad levels of societal consensus. Indeed,
many (if not most) of the great achievements of the American national government have
come about during the periods of broad bipartisan consensus. However, over the past
twenty-five years, we have witnessed the near collapse of such a consensus, at least
among political elites. By almost all measures of partisan polarization, the divide
between Democratic and Republican members of Congress have widened deeply over the
past twenty-five years, reaching levels of partisan conflict not witnessed since the 1920s.
Figure 1 illustrates the growing divergence of House Democrats and Republicans as
measured by DW-NOMINATE scores.1
Figure 1
1
For a discussion of these scores, see Poole and Rosenthal 1997 and McCarty, Poole, and Rosenthal 1997.
There is a small, but rapidly growing literature on the causes of the recent partisan
polarization stressing such factors as the realignment of Southern politics (McCarty,
Poole and Rosenthal 1997, 2003; Perlstein 2002; Stonecash, Brewer, and Mariani 2003),
increasing economic and social inequality (McCarty, Poole, and Rosenthal 1997, 2003,
Stonecash, Brewer, and Mariani 2003, Phillips 2002, Hicks 2003, Rosenthal n.d.), the
effects of congressional districting (McDonald and Grofman 1999; Carson, Crespin,
Finocchiaro, and Rohde 2003), and party-enhancing legislative reforms (Rohde 1991,
Snyder and Groseclose 1999, but see McCarty, Poole, and Rosenthal 2000).
A growing
number of scholars have also studied the effects of elite polarization on mass behavior
finding significant effects on the structure of mass partisanship (Hetherington 2001 and
McCarty, Poole, and Rosenthal 2003) and on the level of trust in government (King 1999
and Hetherington nd). However, relatively less attention has been paid to the effects of
polarization on public policy outcomes.2 In this essay, I propose to explore four primary
hypotheses about the effects of polarization on public policy in the United States.

Polarization makes it harder to build legislative coalitions, leading to policy
“gridlock.”

Polarization is not ideologically neutral; it has a conservative effect, especially on
economic and social policy.

Polarization has had negative effects on the efficient functioning of the
administrative state and the judiciary.
2
An exception is the excellent review essay of Rosenthal (2003).

Polarization has fundamentally altered the balance of power among our national
institutions at the expense of Congress. It has encouraged executives and judges
to act unilaterally without legislative consent.
Many of these propositions are not original to me, and have been developed in supported
in diverse research endeavors. However, there has been little attempt to provide a
systematic account of these diverse phenomena and link them explicitly to political
polarization. Thus, my plans are to synthesize a number of strands of the literature on
American political institutions around the questions of the consequences of partisan
polarization for contemporary policymaking and institutional performance. In those
instances where I identify gaps in the literature on key questions, I will supplement with
original data analysis on the effects of polarization on legislative productivity and policy
outcomes.
I now sketch the rough contours of the argument.
Polarization and Gridlock
Polarization may simply produce greater variation in policy, at times producing
new policy initiatives and at other times rolling them back. However, given the
dispersion of authority in American policymaking systems, there is strong theoretical
reason to believe that the main effect of polarization is to produce less public policy.
Systems of separation of powers and bicameralism require an extraordinary level of
consensus to pass new legislation so that the enacting coalitions are quite often required
to be bipartisan (Krehbiel 1999).
Two broad perspectives have been applied to explain patterns in significant
legislation in the post-war period: partisan theories and pivot theories. It is easy to see
the crucial role that partisan polarization plays in both. In partisan theories, new policies
emerge through inter-branch bargaining with partisan actors. Therefore, when different
branches are controlled by different parties (e.g. divided government) significant policy
enactments are less likely to emerge. However, such a prediction depends on the extent
of policy disagreement are across parties. Clearly, executive-legislative relations during
the Eisenhower years were quite different than the inter-branch confrontations of the late
1990s. Thus, predictions about the effect of divided governments should be conditioned
on the level of partisan polarization. The fact that increased polarization has occurred
coincident with increased frequency of divided government suggests a double-whammy
against significant policymaking.3
Pivot models such as those proposed by Krehbiel (1999) and Brady and Volden
(1998) also suggest a key role for polarization in policymaking. These models identify
necessary conditions for policy change based on the support of pivotal actors. They
argue that the two binding constraints on policymaking in the U.S. are the presidential
veto and cloture in the Senate. Thus, new policies require a House majority, sixty
senators to bring cloture, and presidential support or a 2/3s vote of each chamber to
override a presidential veto. These models define the “gridlock interval” as the region of
the policy space between the senator pivotal on a presidential veto (the 33rd or 67th most
conservative depending on whether or not the president is a liberal or conservative) and
the senator pivotal on cloture (currently the 40th or 60th senator depending on the
3
There is a largely unresolved debate within political science about the causes of the increased frequency
of divided governments. While the claim is hotly contested, Fiorina (1996), Alesina and Rosenthal (1995),
and Mebane and Sekhon (2002) argue that divided governments are caused by the desire of moderate
voters to balance ideologically polarized parties to produce moderate policies. Since the increase in
polarization increases the need for such balancing, recent low levels of policymaking may be suffering
from the single whammy of polarization.
president’s position). Prior to the liberalization of cloture in 1975, the “filibuster” pivot
was the 33rd or 67th senator.
Any policy whose status quo lies in this interval will not be
changed because at least one of the two pivotal actors would veto any move. Thus, when
the gridlock interval is large, significant policymaking will be rare.
Since the definition of the gridlock interval is non-partisan, there need not be any
one-to-one connection between partisan polarization the width of the gridlock interval.
However, as we can see from Figure 2, there is a very strong correlation.
Figure 2
Partisan Polarization and the Width of the Gridlock Interval
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Gridlock Interval Width
Senate Polarization
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More than ¾’s of the variance in the width of the gridlock interval in the post-War
period is accounted for by polarization and the 1975 reforms. However, the concepts are
statistically distinct enough to incorporate both into econometric models.
Beyond its direct consequences for the difficultly of legislative coalition-building,
partisan polarization may have other effects that retard policymaking. For example, King
(1997) and Hetherington (nd) argue that elite polarization has contributed to lower levels
of trust in government which in turn weakens the public’s demand for redistributive
programs. Greater polarization may also increase the incentives to engage in strategic
disagreements or the “blame game” which lead to bargaining failure and gridlock
(Gilmour 1995, Groseclose and McCarty 2000).
My hypotheses can be tested on existing data sets such as that collected by David
Mayhew in his landmark study of major legislative enactments following World War II.
Below are results from a simple regression where a measure of party polarization (from
the U.S. House) has been added to Divided Government (standard errors in parentheses).
Major Laws = 27.12 + .168*Divided Government –25.6*polarization
(7.32) (1.99)
(12.29)
The effect of polarization is very substantial, accounting for a difference of seven major
laws between its trough in 1968 and its peak in 1999 (the average number of major laws
is only 11). As would be suggested by the partisan theory, I included an interaction
between polarization and divided government but it was never significant and generally
had the wrong sign. I also tried to use the measure of the gridlock interval in addition to
polarization, but its coefficient had the wrong sign.
I have also extended this analysis to the more fine-grained coding of legislation
developed by Howell, Adler, Cameron, and Riemann (2000). They classify new public
laws as corresponding to four levels of significance - level A corresponding roughly to
Mayhew’s data though trivial enactments at level D. If I run the same model as above
(with or without a linear time trend), polarization has a statistically and substantively
significant negative effect on legislation at all levels, save D. It turns out that
polarization actually increases the output of triviality.
Thus, my preliminary and admittedly crude analysis is consistent with
polarization having a large negative effect on the legislative output of Congress.
The Conservative Bias of Polarization
The increased propensity for gridlock and stalemate can have profound
consequences for policy outcomes. First, a politically polarized Congress will have
difficulty in responding to economic shocks.4 Second, gridlock erodes the value of noninflation indexed social benefits by preventing the legislative actions necessary to prevent
the erosion of real benefit levels. Over the long term the level of non-indexed benefits
will converge to the levels preferred by the most fiscally conservative pivotal decision
maker. This dynamic suggests that, especially in the case of social spending and nonindexed programs, political polarization biases policy in a fiscally conservative direction.
As an example of this phenomenon, consider the Federal minimum wage. While
there have been numerous unsuccessful attempts to index it to the cost of living, absent
new legislation, inflation erodes its real value. Absent deflation, the status quo is always
moving in a conservative direction.
Thus, if the conservative pivot moves to the right,
there should be fewer and smaller adjustments to the nominal rate, depressing the real
value of the wage. Below I report the estimates of a simple model of the annual real
minimum wage since its inception in 1936. The primary independent variables are
polarization, a dummy variable for unified Democratic governments, an interaction
between polarization and unified government, and a time trend.
4
For evidence that divided government limits the response of state governments to fiscal shocks, see
Poterba (1994) and Alt and Lowery (1994).
Real Min. Wage = 11.18 -14.01*Polar +3.55 *UniDem – 5.75*Polar*UDG + .092*year
(.078) (1.37)
(1.51)
(2.59)
(.007)
R2 =.743
We can see that polarization has a large, depressing effect on the level of the real
minimum wage. In fact, the difference between the predicted wage at minimum level of
polarization and the maximum level is about $5. Polarization has also wiped out the
Democratic premium on the wage. At the minimum level of polarization, the real wage
is about $.60 higher during unified Democratic governments. At its maximum level,
Democratic governments actually lead to lower real minimum wages.5
This analysis can be extended with a variety of other data on specific policy
outcomes. In particular, I can supplement it with preliminary results of my work on the
relationship between polarization and TANF policies in the U.S. states.
Polarization and the Executive and Judicial Branches
One of the clearest manifestations of partisan polarization is increasing level of
contention associated with presidential nominations to executive and judicial positions.
The “confirmation mess” not only has the potential to drive otherwise qualified
individuals from pubic life, but contributes to large numbers of vacancies in the
American bureaucracy and judiciary which impairs the effectiveness of these institutions.
In a recent study of executive appointments, McCarty and Razaghian (1999) find
very strong evidence that party polarization in the Senate has contributed to the dramatic
increase in the length of time required to confirm appointees that is demonstrated in
Figure 3. In their model specification for the post-WWII era, they estimate the following
5
I would again like to stress the preliminary nature of these results.
effects for divided government, partisan polarization, and their interaction (standard
errors in parentheses):
ln(confirmation time) = -0.988*divided + 1.459*polar + 2.155*polar*divided + other controls
(0.350)
(0.469)
(0.610)
Given this specification, the polarization since the 1970s has increased confirmation
times 35% during unified governments and about 90% during divided governments.
While the effects on individual nominees are not large (perhaps a month or more on
average), accumulating them over hundreds of nominees has had a large impact on the
staffing of the executive branch.
Figure 3
The Growth of Confirmation Delay in Executive Offices
Median days to confirmation
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While they do not consider polarization directly, Binder and Maltzman (2002) find that
the distance between the president and the median of the opposite party has a large effect
on the duration of the confirmation process for federal judges. They find that a two
standard variation in this distance lowers the daily probability of confirmation by 60%.6
Since polarization accounts for much of the variation in this measure, this is strong
evidence that polarization is consequential for the large vacancy rates in the federal
judiciary. 7 In my essay, I’ll reexamine Binder and Maltzman’s data to look specifically
for a polarization effect.
Perhaps more important than polarization’s effects on the confirmation process is
the question of to what extent the courts themselves are polarized. Using data on the
ideal points of Supreme Court justices developed by Martin and Quinn (2002), I have
plotted the difference between the 67th percentile conservative and the 33rd percentile
conservative on the court for each year. While the pattern does not match the patterns of
for the House and Senate, it is worth noting that this measure reached its all-time high
shortly after the confirmation of Breyer and continues to increase even absent turnover on
the court. There is strong reason to believe that the lower federal courts are even more
polarized than the Supreme Court, especially across circuits. In the larger essay, I will
pursue such a claim.
6
In addition to the different measures, direct comparison of the McCarty and Razaghian results with those
of Binder and Maltzman is difficult due to the different statistical methods employed. I will attempt to
obtain their data to facilitate the direct comparison.
7
Currently, there are 18 vacancies (10%) on the U.S. Court of Appeals including 12 which have been
designated emergencies due to caseload backlogs.
Figure 4
Polarization on Supreme Court
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Polarization and the Separation of Powers
The power of a legislative body lies in its ability to make laws. As I argued
above, a direct effect of partisan polarization is that it impedes the legislative process.
However, there is little reason to believe that it similarly impedes other actors in the
policy process. A large number of positive theories of policymaking have stressed that
an inability to pass corrective legislation allows much greater autonomy for executive and
judicial actors in the policy process.8 Several recent empirical studies back-up such
claims. Howell (2003) finds evidence that presidents are more likely to act unilaterally
during periods of executive-legislative conflict. Lewis (2002) finds that presidents are
more likely to create agencies through reorganization authority rather than seek a new
statute when inter-branch preferences diverge. Such agencies, he finds, are much less
durable and more politicized than statutory agencies.
8
For example, see Ferejohn and Shipan (1990) and Moe and Howell (1999).
With respect to the courts, Farhang (2003) finds that Congress is much more
likely to empower private litigants and courts to enforce federal statutes rather that
executive branch bureaucrats when the preferences of the president and congressional
majorities diverge. Thus, he argues that a significant source of the litigation explosion is
the result of partisan polarization.
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