Chapter 35 — Key Takeaways

What the chapter establishes

Gerrymandering is real, measurable, and consequential. A drawn map can shift the partisan composition of a state's congressional delegation by five to ten seats, with documented effects on the U.S. House majority and on individual representatives' voting behavior.
Gerrymandering is not the only — or even the largest — driver of safe House seats. Geographic sorting, the spatial concentration of Democrats in urban areas and Republicans in rural areas, automatically produces lopsided districts in single-member-district plurality systems even under neutral maps.
Both major parties gerrymander when they have unified state-government control. The 2010-cycle Republican gerrymanders were the most aggressive single-cycle effort in modern history; Democrats gerrymandered the same cycle in Maryland and Illinois and again in New York in 2022. The asymmetry in 2010 was driven by unusual Republican opportunity in a wave year, not by essential differences between the parties.

Redistricting is the lawful, scheduled redrawing of legislative district lines after each decennial Census; it is unavoidable.
Gerrymandering is the strategic drawing of lines to advantage a party, an incumbent, or a faction; it is a kind of redistricting, not a synonym.
Partisan, racial, and incumbent-protection gerrymandering are distinct types with different legal doctrines applying.
Packing and cracking are the two basic techniques. Packing concentrates the opposing party's voters into a few districts where they win by huge margins; cracking spreads them across many districts where they fall just short.
Race-based dilution is prohibited by Section 2 of the Voting Rights Act; race-as-predominant-factor maps are subject to strict scrutiny under Shaw v. Reno. The two doctrines pull in different directions; mapmakers must navigate the gap.

Federal partisan-gerrymandering claims are non-justiciable after Rucho v. Common Cause (2019). Federal courts will not strike down maps for being too partisan.
State-constitutional partisan-gerrymandering claims are alive in several states; principal cases include League of Women Voters v. Commonwealth (PA 2018), Harkenrider v. Hochul (NY 2022), Clarke v. WEC (WI 2023), and the contested Harper v. Hall doctrine in North Carolina.
Voting Rights Act Section 2 dilution claims were strengthened by Allen v. Milligan (2023), which required Alabama to draw a second majority-Black district and reaffirmed the Gingles framework.
The Independent State Legislature theory in its strong form was rejected by Moore v. Harper (2023), preserving state-court review of state legislatures' federal-elections rules.
Preclearance under Section 5 of the Voting Rights Act is dead after Shelby County v. Holder (2013); Section 2 is the principal VRA tool for redistricting challenges.

Most states default to legislative drawing, with the governor's veto (in most states) and judicial review (always).
Independent commissions operate in Arizona, California, Michigan, Colorado, and (in modified form) Virginia.
Bipartisan commissions operate in New Jersey, Washington, and Connecticut.
Non-partisan staff drafting with legislative ratification operates in Iowa.
The 2020 Census reapportionment moved seats: Texas +2, Florida/NC/CO/MT/OR +1; NY/IL/MI/OH/PA/WV/CA -1.

Efficiency gap measures the asymmetry in wasted votes; partisan symmetry assesses whether a 50-50 vote produces a 50-50 seat split; mean-median difference detects packing-driven bias; compactness measures geometric shape; simulation-based methods compare enacted maps against thousands of computer-generated alternatives.
No single measure is definitive. Maps are best evaluated against several measures in combination.
The 2010-cycle Republican gerrymanders fell as outliers under multiple measures; the 2020-cycle's partisan bias is smaller but still tilted Republican by a few seats nationally.

Independent commissions have produced more compact, less partisan-biased maps in Arizona and California, though "independence" is contested in practice.
Non-partisan staff drafting (Iowa) has worked but in a small, geographically simpler state.
Algorithmic redistricting is transparent but rule-dependent; rule choices are themselves political.
Multi-member districts with proportional voting would reduce gerrymandering's consequences but require federal statute repeal of the 1967 Uniform Congressional District Act.
Federal anti-gerrymandering legislation (John R. Lewis VRA Advancement Act, Freedom to Vote Act) failed in 2022 due to Senate filibuster.
Reform asymmetry — most reforms have come through ballot initiatives, which exist in some states (mostly blue and purple) but not others (mostly red).

The progressive view holds that competitive districts force appeals to the median voter and reduce primary-driven extremism.
The conservative critique holds that competitive districts may increase polarization by forcing incumbents to satisfy activist primary bases that are more extreme than the district median.
Empirical evidence is mixed; the relationship depends on primary structure, activist density, and partisan landscape. Reformers and defenders of safe seats both overstate.

It has not declared partisan gerrymandering unconstitutional; it presents the strongest version of each side.
It has not endorsed any specific reform; each option has merits and costs.
It has not predicted the next decade; the 2030 cycle depends on the 2030 Census, state-legislative composition, state-court compositions, and federal-statutory developments.

The Democracy Audit (this textbook's progressive project) culminates in this chapter for the redistricting dimension: students audit their own district's history, compactness, and competitiveness.
REDMAP (Case Study 01) and the 2022 New York Democratic gerrymander (Case Study 02) illustrate that both parties gerrymander when given the opportunity.
The 2024 election (the textbook's running election example) operated under maps drawn in 2021–22 and modified by 2022–24 court action; the chapter's analysis applies directly to the cycle students lived through.