Gerrymandering is the manipulation of election district boundaries to favor a particular party or candidate. Every ten years, after the census, states redraw congressional and state legislative maps to reflect population changes. Whoever controls that drawing can shape who wins for a decade — and, increasingly, can redraw mid-cycle too.
The core techniques are simple enough to spot once you know them. Cracking splits a group of disfavored voters across several districts so they are too small a share to win anywhere. Packing does the opposite: it crams disfavored voters into as few districts as possible, where they win by huge margins but waste votes that could matter elsewhere. Map drawers often use both at once.
Where did the word come from?
The name is a two-century-old accident. In 1812, Massachusetts Governor Elbridge Gerry approved redrawn districts designed to keep his party in power. According to PBS NewsHour, a Library of Congress archivist showed the original Boston Gazette of March 26, 1812, which carried the first "gerrymander" cartoon: a newspaper editor saw a salamander in the map's outline and fused it with Gerry's name. The image spread to newspapers across the country — what one scholar interviewed by PBS calls probably the first viral meme in American politics.
The practice is older than the word. PBS reports that historian Nick Seabrook, author of "One Person, One Vote," traces manipulated districting to George Burrington, a colonial governor of North Carolina in the 1730s, who redrew assembly districts to blunt opposition to his taxes and fees — with no legal obligation to change the lines at all. We covered a connected angle in What is a Public Editor: Who Polices the Press? The Ombudsman Model, Explained.
How do you spot packing and cracking on a map?
Look at the margins, not the shape. A packed district is one the favored party wins by an overwhelming share — far more votes than needed — while nearby districts are won narrowly. A cracked district is the mirror image: the disfavored group holds a solid but losing share in several districts at once. Both patterns waste votes, and wasted votes are the whole point.
Shape is a poor guide. As the Brennan Center for Justice explains, a skilled map drawer can produce cracked and packed districts that look neat and square yet skew heavily toward one party. Odd shapes, meanwhile, may simply follow a river or city boundary, or keep a shared community intact. Judging fairness by outline alone will mislead you.
The Brennan Center points to North Carolina's congressional map as a case in point. The lines look ordinary, but they sort voters with enough precision that Republicans are virtually assured of winning 10 of the state's 14 congressional races, and could win as many as 11 — a lopsided outcome for a perennial battleground state that regularly elects Democrats to statewide office.
Why does this decide elections before votes are cast?
Because district lines, not just voters, determine seat counts. In a gerrymandered map, outcomes are close to guaranteed even when preferences at the polls shift sharply. In extreme cases, the party that drew the map can win a majority of seats while winning only a minority of the vote statewide. That is the structural problem: politicians choose their voters rather than the reverse.
The stakes are not hypothetical. Per Brennan Center estimates, maps used in the 2024 election carried on average a net 16 fewer Democratic or Democratic-leaning districts than maps meeting the anti-gerrymandering standards in the stalled federal Freedom to Vote Act. North Carolina shows how one state can move the national balance: under a court-drawn map in 2022, the state sent an even split of Democrats and Republicans to the U.S. House. After the state supreme court reversed course and stopped policing partisan gerrymandering, the legislature redrew the map — and after 2024, three Democratic districts flipped to Republicans, enough to help hand the GOP a slim House majority. For related coverage, see How Federal Mandates Hit State and City Budgets.
Both parties do it. The Brennan Center notes that Illinois Democrats redrew their map to leave Republicans with just 3 of 17 seats, the fewest since the Civil War. Abuses are most frequent, the Center finds, when one party has sole control of map drawing, with little transparency and partisan concerns ahead of fair representation.
What changed with the courts — and the mid-decade redraws?
Two things, and they compound. First, the Supreme Court ruled in 2019 that gerrymandered maps cannot be challenged in federal court. The redistricting cycle after the 2020 census was the first under that ruling, and the Brennan Center describes gerrymandering since as worse and more frequent.
Second, states have begun redrawing outside the once-a-decade cycle. PBS reports that mid-decade redistricting intensified when Texas, at President Trump's request, redrew its congressional maps to try to add five Republican seats. California's governor responded by calling a special election to pick up more Democratic seats. In all, PBS counts nine states redrawing mid-decade ahead of the 2026 midterms: Texas, California, Utah, Ohio, Tennessee, Louisiana, Alabama, Florida and North Carolina. Nearly 35 million Americans will vote in congressional districts redrawn ahead of those midterms.
The analysis: the record points to a ratchet. Once one party redraws mid-decade for advantage, the other faces a choice between unilateral restraint and losing seats — and the sourced record so far shows states choosing seats. What would change that reading is a binding rule: a state or federal standard that constrains mid-cycle redraws, or courts willing to police partisan maps again. Neither exists at the federal level today.
Who decides the lines, and can that be fixed?
In most states, the legislature draws the maps, subject to the governor's veto where one exists. That is why single-party control of state government translates so directly into map control. The reform response has been to move the pen: independent or bipartisan redistricting commissions, which take the job away from the legislators whose seats are at stake.
Other guardrails exist in principle — requirements that districts be contiguous, roughly equal in population, and in some states not split counties or communities. Enforcement varies widely by state, and the 2019 federal ruling removed one major backstop. Voters in several states have passed commission reforms by ballot initiative, though the details differ state by state and this article does not rate which states' maps are fair.
What this means for your vote
Three practical takeaways. First, check who draws your state's maps — legislature or commission — because that answers most questions about incentives. Second, judge maps by vote margins and seat shares, not by outline; a tidy shape tells you nothing. Third, remember that redistricting also happens locally, for county commissions, city councils and school boards, where the same packing and cracking techniques apply with far less scrutiny.
District lines are administrative objects with electoral consequences. Reading them well means asking one question of every map: how many votes were drawn to be wasted, and for whom. The evidence above does not settle every state's case, but it shows the mechanism clearly enough to check the numbers yourself.
