Why Redistricting Is So Important, In 3 Charts

Texas Republicans' move to redraw their legislature representation mid-decade and Democrats' retaliatory redistricting efforts person captured nationalist attraction for a very elemental reason: How House districts are drawn tin style American authorities for years.

Gerrymandering mostly reduces nan number of competitory races, and it tin fastener successful astir immovable advantages for 1 statement aliases another. Under nan caller representation proposed successful Texas, nary seat’s statesmanlike ballot would person been decided by azygous digits successful 2024, and Republicans would person a path to pad their constrictive legislature majority successful nan 2026 midterm elections. This intends much group could reside successful legislature districts nether coagulated power of 1 party.

NBC News analyzed really nan mobility of who draws nan maps — and really they do it — tin style elections for years afterward.

The quality betwixt safe seats and competitory districts

Who draws territory lines tin make nan quality betwixt contested wide elections successful a authorities successful November and elections that are hardly much than formalities.

NBC News analyzed each House title successful nan state from 2012 to 2020, nan past afloat 10-year redistricting cycle, based connected really each territory was drawn. In states wherever authorities legislators drew nan maps, single-digit races (elections successful which nan winners won by little than 10 percent points) were rarest. Only 10.7% of House races fell into that competitory category.

There are plentifulness of reasons that don't impact gerrymandering. For 1 thing, voters of some parties person increasingly clustered successful caller years, leaving less places astir nan state that are politically divided.

Still, gerrymandering does play a important role. When commissions aliases authorities aliases national courts drew nan lines past decade, nan complaint of competitory elections jumped, though safe seats are still overwhelmingly likely. Competitive elections were particularly prevalent successful states pinch court-drawn districts: 18.1% of races successful those states had single-digit margins from 2012 done 2020.

A look astatine Pennsylvania, whose legislative-drawn representation was thrown retired and replaced successful 2018 by nan authorities Supreme Court, illustrates nan melodramatic alteration that tin travel based connected who draws legislature lines. The aforesaid authorities pinch nan aforesaid voters surviving successful nan aforesaid places abruptly had galore much competitory elections.

From 2012 done 2016, conscionable 3 of Pennsylvania's 54 House wide elections nether nan first representation had single-digit margins.

After nan authorities Supreme Court threw retired nan representation and imposed a caller one, nan number of battleground races bumped up. Eight of 36 House races had single-digit margins successful 2018 and 2020.

Meanwhile, up of nan 2026 midterms, The Cook Political Report pinch Amy Walter rates 40 House districts arsenic toss-ups aliases somewhat leaning toward 1 party. More than half (23) of those 40 competitory districts are successful states wherever commissions aliases courts drew nan maps.

How a state's partisanship compares pinch whom it sends to Congress

The powerfulness of nan redistricting process tin crook a state's practice successful Congress distant from its wide partisanship, pinch wide differences betwixt nan statewide ballot successful immoderate states and nan constitution of their House delegations.

Take Illinois, for example, wherever Donald Trump sewage 44% of nan ballot successful 2024. Republicans clasp only 3 of nan state’s 17 seats successful Congress, aliases 18%. (NBC News is looking astatine statesmanlike information alternatively of House information present because immoderate races are uncontested.) And moreover though Trump sewage 38% of nan ballot successful California past year, Republicans clasp only 17% — that’s 9 seats — of nan state’s 52 legislature districts.

On nan different broadside of nan ledger, Trump sewage 58% support successful South Carolina past year, and 86% of nan state's House delegation is Republican. In North Carolina, 51% voted for Trump past year, and Republicans person 71% of nan delegation.

The comparison betwixt House seats and statesmanlike predetermination capacity isn’t perfect. But it demonstrates that really territory lines are drawn tin make different results from what statewide results mightiness suggest.

Right successful nan mediate of nan floor plan is Virginia. Its 11 legislature districts divided 6-5 for Democrats, meaning Republicans clasp astir 46% of nan state’s seats successful Congress, and Trump won 46% of nan ballot successful Virginia past year.

Also, conscionable because a state’s maps favour 1 statement compared pinch nan statewide results aft 1 predetermination doesn’t mean nan redistricting process was biased. Tightly divided Pennsylvania has 7 Democrats and 10 Republicans successful Congress, and 3 GOP-held districts are rated arsenic toss-up aliases lean-Republican races successful 2026, according to nan Cook Political Report.

Each authorities charts its ain course

Since each authorities is responsible for handling its ain redistricting, nan process is different depending connected wherever you look, giving immense powerfulness to different institutions authorities by state.

In 27 states, legislatures approved nan maps. In seven, independent commissions approved them, 7 had court-approved maps, 2 had governmental commissions, and 1 state’s maps were approved by a backup commission, according to information from Loyola Law School. (The six states that elite only 1 personification to nan House don’t tie caller legislature maps.)

Loyola Law School’s "All About Redistricting" website defines leader commissions arsenic panels elected officials tin service connected arsenic members. The website defines backup commissions arsenic backup procedures if legislatures can’t work together connected caller lines.

Some independent redistricting commissions aren't arsenic powerful arsenic those successful different states. New York has an independent commission, but nan Legislature overrode its map and passed its ain successful 2024.