Gerymandering
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Transcript Gerymandering
The Gerrymander
How to Divide and Conquer your Enemy
A Case Study on Map Use Abuse
Gerrymander Origin
Gerrymander, or Gerrymandering, is derived from
Gerry + Salamander
Elbridge Gerry was the governor of Massachusetts before
becoming Vice President under James Madison.
The misshapen district which was drawn and passed
through the Massachusetts legislature in 1812 by the
Democratic Republicans.
The district resembles a salamander.
This is a form of redistricting in which electoral
districts are manipulated for an electoral advantage
for one political party.
This careful shaping of the voting district gave them and
advantage over there Federalist party rivals.
Gerrymander Origin
Elbridge Gerry, the
5th Vice President of the
United States. In office
from March 4, 1813, to
November 23, 1814,
under President James
Madison
This satirical cartoon
depicting a district in
Essex County,
Massachusetts, as a
dragon, was printed in
the Boston Gazette,
March 26, 1812. The
electoral districts were
drawn by DemocraticRepublican members of
the Massachusetts
legislature to favor their
incumbent party
candidates. Governor
Elbridge Gerry signed
the redistricting into
law, although
reluctantly.
Gerrymander Origin
Redistricting by gerrymandering is typically used by
those of a political party in power, or the
incumbents.
This redistricting will then advantage their own
party, or disadvantage the opposing party, or
members of a racial, national, linguistic, religious, or
class group.
Redistricting can especially favor a particular political
party in single-winner electoral systems that elect
representatives to represent voting districts.
Such systems, are called first past the post, or winner
takes all.
Typically, such voting systems favor few political parties,
e.g., our democratic and republican parties.
Example of Positive Effects of
Gerrymandering
In Arizona, the Hopi native American tribe is
surrounded by the historically rival Navaho
tribe.
In this case there is good cause to elect different
representatives to the two tribes that are
geographically interlocked.
Another, more contentious case, is a narrow
California congressional district along the
coast separate from the inland district.
The two districts have different concerns that do
not always overlap.
Gerrymandering Techniques
Two gerrymandering techniques, packing and
cracking, allow maximizing votes for one
party while minimizing votes for the
opposition.
Packing concentrates opposition voters in a
few districts that are already a majority in
that party.
Cracking breaks down regions that will dilute
the opposition so that a slight majority for the
other party.
Gerrymandering Example Diagram
Left: Four districts of even “Red” and “Green” party voters, 8
from each party.
Right: Redrawing the balanced electoral districts in this example
creates only one packed district of 14 green voters.
The remaining 18 green voters are cracked across the 3 other
districts. The result is a 3-to-1 advantage for the “Red” party.
Gerrymandering Effects
The effects of gerrymandering can be detrimental to the
democratic process
Gerrymandered districts favor incumbents that are difficult to
unseat in elections, thus creating safe seats.
Safe districts with incumbents with less incentive to govern
by constituents’ needs
Proportional or descriptive representation is then altered
Meaningful campaigns are also influenced, further
demoralizing voters.
In the 2002 election, only four incumbents in the US
Congress were defeated, the lowest number in history.
This was in part due to redistricting and gerrymandering by
incumbents.
Gerrymandering Example:
Arizona's 2nd congressional district
The unusual
division was
not drawn to
favor
politicians, but
to separate the
Hopi and the
Navajo tribes,
due to historic
tensions.
Since the Hopi reservation is completely surrounded by the
Navajo reservation, and in order to comply with current
Arizona redistricting laws, some means of connection was
required that avoided including large portions of Navajo land,
hence the narrow Colorado River connection.
Gerrymandering Example:
Texas’s 22nd congressional district
This district
was the result
of redistricting
in 2003, when
Texas congress
had become
republican, the
first time since
Reconstruction
This mid-decade redistricting resulted in six additional seats
in US congress
Gerrymandering Example:
California’s 38th congressional district
District 38 was
produced by
California's
incumbent
gerrymandering,
as home to
democrat Grace
Flores Napolitano,
who ran
unopposed in 2004
Gerrymandering Example:
Illinois’s 4th congressional district
The unusual
"earmuff" shape
connects two
Hispanic
neighborhoods
while remaining
contiguous by
following
Interstate 294.
Gerrymandering Example:
Texas’s 25th congressional district
U.S. congressional districts covering Travis County (outlined in
red) in 2002, left, and 2004, right.
In 2003, Republicans in the Texas legislature redistricted the
state, diluting the voting power of the heavily Democratic
county by parceling its residents out to more Republican
districts.
The district in orange is the infamous "Fajita strip" district 25
(intended as a Democratic district), while the other two
districts (10 and 21) are intended to elect Republicans.
District 25 has now been redrawn as a result of the 2006 U.S.
Supreme Court decision, and is no longer a "Fajita strip."
Gerrymandering Example:
Texas’s 25th congressional district
U
Gerrymandering Example:
Texas’s 25th congressional district
The conservative 51st
District was renumbered the
50th District after the 2000
census, and was
gerrymandered to include
the more conservative
community of Clairemont
Mesa, and to exclude the
relatively liberal areas of La
Jolla and Univ. of Calif. at
San Diego, which were
moved to the more-liberal
53rd District.
Remedies
Redistricting was only allowed after the ten year
census
The United States Supreme Court upheld all of the
2003 Texas redistricting engineered by former House
Majority Leader Tom DeLay, except for the "fajita"
district, which would have affected racial and ethnic
minority groups.
This decision now allows politicians to redraw and
gerrymander districts as often as they like to protect
their political parties and seats, provided they do not
harm racial and ethnic minority groups.
Remedies
Some states have taken or considered taking steps to
revoke this rule
A separate non-partisan redistricting authority would
choose districts in order to prevent abuse.
Some examples are:
Washington State Redistricting Commission
Arizona Independent Redistricting Commission
Rhode Island Reapportionment Commission
New Jersey Redistricting Commission
The city of San Diego also uses such a system according to
its municipal charter.
Shape Constraints
A GIS remedy is consider the shape of a district as a limiting
factor.
One way to define shape is to compare a parcel’s perimeter
length to its area.
P
This is:
Shape S
4A
This value is dimensionless
The value for a circle is 1
The value for a square is 1.1284
The value for a rectangle five times longer than its end is
1.5139
Limiting this number below a certain value would also limit
gerrymandering.
References
Elbridge Gerry, Wikipedia,
http://en.wikipedia.org/wiki/Elbridge_Gerry
California's 50th congressional district, Wikipedia,
http://en.wikipedia.org/wiki/United_States_House_of_Representati
ves,_California_District_50
Politics of Texas, Wikipedia,
http://en.wikipedia.org/wiki/Politics_of_Texas#Redistricting_Dispu
tes_and_the_1990s
Salamander, Wikipedia,
http://en.wikipedia.org/wiki/Image:Salamandra_salamandra_%28M
arek_Szczepanek%29.jpg
Longley, Paul A., Goodchild, Michael F., Maguire, David J., Rhind,
David W., Geographic Information Systems and Science, Publisher:
Wiley