1. The Gerrymander How to Divide and Conquer your Enemy A Case Study on Map Use Abuse

2. 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

3. Elbridge Gerry, the 5th Vice President of the United States. In office from March 4, 1813, to November 23, 1814, under President James Madison Gerrymander Origin

4. 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 Democratic- Republican members of the Massachusetts legislature to favor their incumbent party candidates. Governor Elbridge Gerry signed the redistricting into law, although reluctantly.

5. 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. Gerrymander Origin

6. 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 to dilute the opposition giving a slight majority to one party.

7. 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.

8. 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 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.

9. Gerrymandering Example: Texas’s 22nd congressional district This mid-decade redistricting resulted in six additional seats in US congress This district was the result of redistricting in 2003, when Texas congress had become republican, the first time since Reconstruction

10. Gerrymandering Example: Illinois’s 4th congressional district The unusual "earmuff" shape connects two Hispanic neighborhoods while remaining contiguous by following Interstate 294.

11. Remedies Some states have taken or considered taking steps to curb gerrymandering 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.

12. 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. This is: 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.