Partisan and bipartisan gerrymandering

• Date: 01 September 2020
• Published date: 01 September 2020
• Author: Chen‐Yu Pan,Hideo Konishi
• DOI: http://doi.org/10.1111/jpet.12433

J Public Econ Theory. 2020;22:1183–1212. wileyonlinelibrary.com/journal/jpet © 2020 Wiley Periodicals, Inc.

|

1183

Received: 5 September 2017

|

Accepted: 30 December 2019

DOI: 10.1111/jpet.12433

ORIGINAL ARTICLE

Partisan and bipartisan gerrymandering

Hideo Konishi

1

|Chen‐Yu Pan

2

1

Department of Economics, Boston College,

Chestnut Hill, Massachusetts

2

Department of Public Finance and

Taxation, School of Economics and

Management, Wuhan University, Wuhan,

China

Correspondence

Hideo Konishi, Department of Economics,

Boston College, Chestnut Hill, MA 02467.

Email: hideo.konishi@bc.edu

Abstract

This paper analyzes the optimal partisan and bi-

partisan gerrymandering policies in a model with

electoral competitions in policy positions and transfer

promises. Party leaders have both office‐and policy‐

motivations. With complete freedom in redistricting,

partisan gerrymandering policy generates the most

one‐sidedly biased district profile, while bipartisan

gerrymandering generates the most polarized district

profile. In contrast, with limited freedom in gerry-

mandering, both partisan and bipartisan gerry-

mandering tend to prescribe the same policy.

1|INTRODUCTION

It is widely agreed upon that election competitiveness has decreased significantly in recent

decades. For example, the re‐election rate of the US House of Representatives has increased

from 91.82% in 1950 to 98.25% in 2004 (Friedman & Holden, 2009). Also, 74 House seats were

won by a margin of less than 55% in 2000, but this number decreased to 24 in 2004 (Fiorina,

Pope, & Abrams, 2011). During the same period, Congress has become quite polarized. In the

1960s, the distribution of the representatives' political positions was concentrated more toward

the center of the political spectrum, with considerable overlap between Republicans' and De-

mocrats' positions. By the 2000s, the positions became sharply twin‐peaked with less overlap.

1

One popular explanation for this phenomenon in the US politics is gerrymandering. Fiorina

et al. (2011) argue that gerrymandering biased toward incumbents, that is bipartisan gerry-

mandering, has an effect on the decrease in competitiveness, since both parties try to secure

their incumbent seats.

2

They also suggest that this decrease in competitiveness may be

1

It is now standard to use a one‐dimensional scaling score (DW‐Nominate procedure on economic liberal‐conservative,

Poole and Rosenthal, 1997) to measure representatives' political positions.

2

Fiorina et al. (2011) state that “Many (not all) observers believe that the redistricting that occurred in 2001–2002 had a

good bit to do with this more recent decline in competitive seats—the party behaved conservatively, concentrating on

protecting their seats rather than attempting to capture those of the opposition.”(see Fiorina et al., 2011, pp. 214–215).

one of the causes of the recent political polarization in Congress, since proposing more po-

larized positions does not jeopardize secured seats.

3

In contrast, partisan gerrymandering is commonly used to increase the power of a political

party, and it may or may not reduce district competitiveness, since the party tries to secure their

incumbents but at the same time may create competitive districts to capture the opposing

party's districts. Recently, there have been many partisan gerrymandering lawsuits against state

legislatures to request redistricting of state congressional maps, including Pennsylvania,

Maryland, Wisconsin, and North Carolina.

4

In these cases, the courts rely on a measure of vote

misrepresentation, the efficiency gap, and heated debates are going on as to whether or not this

is an appropriate measure to use (Bernstein & Duchin, 2017; Chambers, Miller, & Sobel, 2017).

5

Since these two methods loom large in US politics and public debates, we go one step further to

see how different the resulting district maps under partisan and bipartisan gerrymandering are,

and how polarized the elected representatives are.

In this paper, we will investigate the difference between optimal partisan and bipartisan

gerrymandering and the effects on representative policy positions in a unified framework. For

this purpose, we introduce party leaders who are not only office‐motivated but also policy‐

motivated, which is also new to the literature. We set up a two‐party political competition

model in which party leaders compete with their candidates' (unidimensional) policy positions

and pork‐barrel promises in each electoral district.

6

We assume that there are minimum units

of indivisible localities with the same population, and that a gerrymanderer partitions the set of

localities to create electoral districts. Each locality has a voter distribution, and we say that the

gerrymanderer has complete freedom in redistricting if the distribution is concentrated on a

point on the political spectrum. With pork‐barrel politics, the party leader understands that

pork‐barrel policies in competitive districts are costly, and therefore she has strong incentives to

collect her supporters in the winning districts to avoid large pork‐barrel promises.

Traditionally, the literature on gerrymandering often discusses two tactics in partisan ger-

rymandering: one is to concentrate or pack those who support the opponent in losing districts,

and the other is to evenly distribute or crack supporters in winning districts. Packing serves to

waste the opposing party's strong supporters' votes, while cracking utilizes the votes of party

supporters as effectively as possible. Owen and Grofman (1988) show that a pack‐and‐crack

policy is optimal when a partisan gerrymanderer has limited freedom in redistricting (a

constant‐average constraint: see the literature review). In contrast, Friedman and Holden (2008)

3

Since polarization has complicated causes, this argument has limitations. Citing that polarization has also been

happening in the Senate, Fiorina et al. (2011, p. 219) suggest that “redistricting is only a minor part of congressional

polarization, or that it is important only in combination with other factors such as closed primaries.”Alternative

explanations for polarization include voters' party sorting and geographical sorting. The former says that voters became

sorted into Republican and Democratic parties in the latter half of 1900s due to party elites' polarization

(Levendusky, 2009). See also Gilroux (2001). The latter says that voters sort themselves into more ideologically

homogeneous districts, causing polarization. The rationale behind this is that districts seem to polarize more between

redistricting than during them (McCarty, Poole, & Rosenthal, 2009).

4

In February 2018, the Pennsylvania Supreme Court blamed the states' district map on partisan gerrymandering, and

told state lawmakers to redraw the state's 18 House districts, which currently favor Republicans.

5

The efficiency gap and the vote‐seat curve are measures based on only two numbers, the vote shares and the seat

shares of the two parties, which may not contain sufficient information to appropriately evaluate partisan gerry-

mandering. As Chambers et al. (2017) correctly recognize, the presence of extremists and election uncertainty should be

taken into account. For example, consider the outcome of conservative bipartisan gerrymandering. It is possible that the

resulting redistricting plan generates extremely polarized policy positions for the elected representatives but is still

perfectly desirable under criteria like the efficiency gap or the seat‐vote curve.

6

We assume that party leaders can choose their candidates' policy positions freely.

1184

|

KONISHI AND PAN