Fact check: Which states have implemented anti-gerrymandering laws?

Executive Summary — What "anti‑gerrymandering laws" actually cover and where reform has happened

States vary widely in what counts as an anti‑gerrymandering law: some have created independent redistricting commissions to remove partisan control, others have state court rulings or statutes limiting partisan maps, and still others have rolled back reforms. The materials provided show at least three partially overlapping lists: a group of states with commission-based reforms (Arizona, California, Colorado, Idaho, Michigan, Montana, Washington) ^{[1] [2]}, a set of state high‑court decisions treating partisan gerrymandering as justiciable (Alaska, Kentucky, Maryland, New Mexico, New York, Ohio, Wisconsin) ^[3], and broader compilations claiming up to 15 states with some anti‑gerrymandering measures though lacking consistency in definition ^[4]. These differences reflect varying legal mechanisms—commissions, statutes, and judicial remedies—rather than a single uniform law.

1. Why lists diverge: competing definitions and legal tools drive confusion

The first key finding is that the question “Which states have implemented anti‑gerrymandering laws?” produces different answers because analysts use different criteria. One set of sources counts states with constitutionally or statutorily created independent citizen commissions as having anti‑gerrymandering measures—Arizona, California, Colorado, Idaho, Michigan, Montana, and Washington—focusing on structural removal of political actors from map drawing ^{[1] [2]}. Another set emphasizes judicial recognition of justiciable partisan‑gerrymandering claims at state high courts, listing Alaska, Kentucky, Maryland, New Mexico, New York, Ohio, and Wisconsin as places where courts will hear such claims ^[3]. A third compilation enumerates a broader roster of 15 states that have implemented various reforms or protections, including legislative and procedural changes, but the compilation mixes commission laws, statutes, and court outcomes, which explains disagreement among sources ^[4]. The split shows methodological divergence more than factual contradiction.

2. Independent commissions: clear legal change with limited geographic reach

Sources that examine independent citizen redistricting commissions converge on a compact set of states that adopted commission models by ballot or statute: Arizona, California, Colorado, Idaho, Michigan, Montana, and Washington ^{[1] [2]}. These reforms share a common anti‑gerrymandering aim—to reduce partisan control over map drawing—yet they differ in commissioner selection, standards for partisan balance, and legal authority. Analyses note that commission effectiveness depends on design details such as who appoints members, how partisan balance is measured, and whether courts can review maps ^[5]. The commission list is recent and precise but does not include states that limit gerrymandering through other mechanisms such as statutory constraints or court rulings, which is why broader lists include additional states ^{[1] [2]}.

3. Courts as reformers: states where judges will hear partisan gerrymandering claims

Another cluster of reform comes from state high courts treating partisan‑gerrymandering claims as justiciable, meaning plaintiffs can challenge maps in state court. Seven state high courts have been identified as doing so—Alaska, Kentucky, Maryland, New Mexico, New York, Ohio, and Wisconsin—creating a judicial avenue for anti‑gerrymandering remedies ^[3]. This path differs from commission models because it relies on litigation outcomes and judicial interpretation of state constitutions or statutes rather than legislative or ballot reforms. Court rulings can produce map redraws, standards, or injunctions, but they are case‑specific and reversible by later court decisions or legislative action, which helps explain why lists based on judicial activity diverge from commission‑based lists ^[3].

4. Broad claims and rollbacks: why some compilations report 15 states

Some compilations present a longer list—reporting as many as 15 states with anti‑gerrymandering laws—by aggregating diverse reforms including commissions, statutes ending practices like prison gerrymandering, and court precedents ^{[4] [6]}. These broader lists are useful to show widespread activity but risk conflating distinct mechanisms: a state that bans prison‑based counting of inmates (Minnesota law ending prison gerrymandering) or a city that adopts independent redistricting is not equivalent to a state constitutional commission or a binding court precedent ^[6]. Political reversals further complicate counts: Missouri’s Amendment 3 rollback illustrates how voter‑approved reforms can be altered or nullified, changing whether a state should be counted as “having” anti‑gerrymandering law ^[7]. Thus larger counts must be read as cumulative snapshots, not uniform legal equivalence.

5. What the evidence implies for policymakers and the public

The practical takeaway is that whether a state “has” anti‑gerrymandering law depends on which legal tool you value: commission reforms, statutory bans, or judicial enforceability. Commission states provide a proactive structural fix in a narrow set of states ^{[1] [2]}, judicially active states enable litigants to attack maps ^[3], and wider compilations capture incremental or local reforms and reversals ^{[4] [7]}. Any definitive public accounting requires specifying criteria—commission adoption, statutory prohibition, or court‑enforced limits—and acknowledging that reforms are dynamic: voter initiatives, court rulings, and legislative rollbacks continue to reshape the landscape ^[8]. For clarity, researchers and advocates should state which mechanism they mean before asserting how many states have anti‑gerrymandering laws.