How Gerrymandering Shapes Elections Before a Single Vote Is Cast

The Salamander That Named a Strategy

In 1812, Massachusetts Governor Elbridge Gerry signed a redistricting plan that carved his state's senate districts into a shape designed to favor the Democratic-Republican Party. One district, winding through Essex County, resembled a salamander on the map. The Boston Gazette coined the portmanteau "gerrymander" — combining "Gerry" with "salamander" — and political cartoonist Elkanah Tisdale drew the creature with wings, claws, and fangs. The name stuck for two centuries. The practice it described is far older: Roman consuls manipulated tribal voting units to advantage their factions, and English borough boundaries were drawn to serve aristocratic interests centuries before Gerry ever signed his infamous bill.

Gerrymandering is the drawing of electoral district boundaries to give one political party, racial group, or incumbent politician a systematic advantage over rivals. In a democracy where the fundamental premise is that voters choose their representatives, gerrymandering inverts the relationship: representatives choose their voters. The manipulation can determine electoral outcomes for a decade or more — the length of a typical redistricting cycle.

How Districts Are Drawn

In the United States, state legislative districts and congressional districts are redrawn every ten years following the census. In most states, the state legislature controls this process — meaning whichever party controls the legislature after the census year controls district lines for the following decade. The same conflict of interest exists at all levels: politicians draw the lines that determine their own electoral fate.

Two primary techniques accomplish partisan manipulation:

• Packing: Concentrating opposition voters into a small number of "sacrifice" districts where they win by overwhelming margins (70–80%+), wasting their votes. A district that was competitive becomes a 70-30 blowout — same votes, different efficiency.
• Cracking: Splitting a concentrated opposition community across multiple districts, diluting its voting power so it cannot elect a representative in any single district. An urban minority that could elect 3 representatives is split into 5 districts where it forms an under-40% minority in each.

Sophisticated modern gerrymandering combines both. Packing a few districts absorbs die-hard opposition voters. Cracking the remaining opposition creates a ring of competitive-looking districts that actually lean safely toward the dominant party. The goal is to win many districts by comfortable but not wasteful margins while forcing the opposition to win a few districts by huge margins.

The 2010 REDMAP Strategy

The Republican State Leadership Committee's 2010 REDistricting MAjority Project (REDMAP) was the most systematic exploitation of gerrymandering in modern US political history. The strategy was explicit: invest resources in state legislative races in key states in 2010 — a census year — to control redistricting after the count. The investment of $30 million produced control of legislatures in key states including Pennsylvania, Ohio, Wisconsin, Michigan, and North Carolina.

The numbers reveal the effect starkly: in states where Obama won decisively, Republican congressional delegations were 2-to-1 or greater. The political geography of concentrated urban Democratic voters made some Republican advantage natural, but the magnitudes reflected deliberate engineering.

Racial Gerrymandering and the Voting Rights Act

Gerrymandering intersects with race through two separate legal frameworks pulling in opposite directions. Section 2 of the Voting Rights Act of 1965 prohibits electoral practices that discriminate against racial minorities, which courts have interpreted to require drawing some majority-minority districts — districts where minorities form a majority and can elect their preferred candidates. This requirement creates majority-minority districts.

But the Supreme Court in Shaw v. Reno (1993) held that racial gerrymandering — drawing district lines based predominantly on race — violates the Equal Protection Clause when the resulting district shape suggests race was the overriding factor. The resulting contradiction: the law simultaneously requires consideration of race (to avoid dilution) and prohibits race from being the predominant factor (to avoid racial classification).

• North Carolina's 12th Congressional District, created after 1990 to be a majority-Black district, was challenged five times before the Supreme Court over its odd, winding shape connecting Black communities across 160 miles.
• Alabama's 2021 redistricting was challenged by the Supreme Court in Allen v. Milligan (2023), which ruled 5-4 that Alabama had violated the VRA by drawing only one majority-Black district despite Black voters comprising 27% of the population.
• The distinction between racial gerrymandering (illegal) and political gerrymandering that happens to correlate with race (legally murkier) remains one of the most contested areas of election law.

The Supreme Court and Partisan Gerrymandering

Rucho v. Common Cause (2019) was the Supreme Court's definitive answer on federal court challenges to partisan gerrymandering: federal courts cannot adjudicate them. Chief Justice John Roberts' majority opinion held that partisan gerrymandering claims present political questions beyond the reach of federal courts, leaving remedies to state courts, state legislatures, and Congress.

The decision did not make gerrymandering legal — it left the question to states. Several state courts subsequently struck down maps under state constitutional provisions. Pennsylvania's Supreme Court struck down the state's congressional map in 2018. North Carolina's Supreme Court struck down state legislative maps in 2022 — then reversed itself in 2023 after the court's partisan composition changed. Ohio's Supreme Court struck down maps six consecutive times, only for a gridlocked redistricting process to leave the original maps in place through court delays.

Reform Approaches

Multiple reform mechanisms have been adopted across US states, with varying results:

• Independent redistricting commissions: California (2008), Arizona (2000), Michigan (2018), and Colorado (2018) created commissions insulated from legislative control. California's commission, with 14 citizens selected through an application and random lottery process, produced maps widely praised for competitive districts.
• Bipartisan commissions: Some states require equal representation from both parties, which prevents single-party control but can produce gridlock — as Ohio's experience demonstrated.
• Algorithm-based redistricting: Several computer scientists have proposed mathematically generating thousands of legally compliant maps and requiring any enacted map to fall within the range of randomly generated alternatives.
• Alternative electoral systems: Proportional representation or ranked-choice voting in multi-member districts reduces gerrymandering's effect by changing the math — when three representatives are elected from one large district, minor parties can gain seats regardless of lines.

Gerrymandering is not unique to the United States. Britain's first-past-the-post system has its own manipulation history; France redistributed constituencies in 1986 to favor specific parties; Israel's complex threshold rules function as a different kind of systemic manipulation. But the US system — decennial cycles, state legislative control, and single-member districts — creates unusually strong incentives and opportunities for manipulation.

The fundamental problem is simple: letting any politically interested party draw its own electoral boundaries is a conflict of interest so obvious that virtually every other functioning democracy has addressed it through independent bodies. The United States remains the notable exception among major democracies — a fact that explains why redistricting cycles produce litigation, controversy, and systematic distortion every ten years without fail.