Keep Factually independent
Whether you agree or disagree with our analysis, these conversations matter for democracy. We don't take money from political groups - even a $5 donation helps us keep it that way.
Which political parties benefited most from gerrymandering in different states over the last 50 years?
Executive summary
Over the last 50 years, both major U.S. parties have engineered maps that advantaged their own candidates in particular states at different times: Republicans secured durable advantages in many Sun Belt and Rust Belt state legislatures and congressional delegations across the 2000s–2010s, while Democrats have controlled and defended heavily gerrymandered maps in states such as Maryland and New York; recent mid‑decade maneuvers (notably Texas in 2025) show Republicans again pursuing aggressive mapmaking [1] [2] [3]. Scholarly work and watchdog groups disagree about the current aggregate national advantage: some analysts (Princeton, PlanScore, Brennan Center reporting) document state‑level partisan gains, while Brookings argues neither party currently enjoys a strong nationwide gerrymander advantage [4] [5] [3] [6].
1. How to read “who benefited” — meaning and measurement
“Benefited” can mean a state legislature or governor used mapmaking to translate votes into a larger share of seats (packing/cracking), or that one party’s control persisted because of maps; measures vary (seat‑vote bias, simulation tools, PlanScore). Princeton’s Gerrymandering Project and PlanScore quantify partisan fairness by comparing actual maps to ensembles of possible maps; the Brennan Center frames gerrymanders as intentionally choosing voters rather than voters choosing politicians [4] [5] [3]. Brookings asserts that, at the national aggregate, neither party currently enjoys a large advantage — highlighting methodological disagreement over how to aggregate state effects [6].
2. Historical arc: Republicans’ mid‑2000s–2010s gains in many states
Analyses tracing the modern GOP strategy show Republicans captured and then used state legislative control after 2010 to draw maps that produced outsized seat totals in battlegrounds (examples cited include Ohio, Florida, Pennsylvania, Wisconsin, Michigan), with storylines that Republican redistricting won unusually large seat shares in states Obama had carried earlier [1]. That era’s maps produced long runs of state legislative majorities and congressional seat advantages in several states; reporters and analysts attribute this to coordinated redistricting plans and modern mapping technology [1].
3. Democratic‑leaning gerrymanders and state examples
Democrats have also produced maps that lock in heavy advantages where they control state government. Notable cases raised by reporting include Maryland and parts of the Northeast where Democrats hold many seats relative to statewide vote share, and instances where state courts or ballot measures (e.g., California’s independent commissions) have been used to counter or entrench maps [7] [8] [3]. The Brennan Center emphasizes both parties have used packing and cracking historically [3].
4. The 2019 Supreme Court decision and its effects
The Supreme Court’s Rucho v. Common Cause decision (covered in state reporting) removed federal constitutional remedies for partisan gerrymandering, pushing fights into state courts and politics; that shift helped produce divergent outcomes across states — some states blocked extreme maps in court, others left them in place [9]. As a result, state‑level rules and courts determine whether mapmaking advantages persist [9].
5. The 2020s: mid‑decade redistricting and a contested cycle (Texas, Utah, others)
The 2020s introduced an escalation of mid‑decade redistricting: Texas Republicans passed a 2025 mid‑decade map intended to add Republican seats (reporting estimates new GOP‑majority districts), provoking litigation over racial and partisan motives; at the same time, courts in states like Utah produced remedial maps that helped Democrats in at least one instance [2] [10] [11]. Reuters, The Guardian and state legal reporting show a patchwork of victories, defeats and ongoing suits that make the immediate beneficiaries state‑specific [12] [13] [9].
6. Competing interpretations: aggregate advantage vs. state battles
Analysts disagree whether gerrymandering currently favors one party nationally. Brookings maintains there is not a large aggregate advantage for either party now, arguing demographic and geographic distributions matter; other outlets and projects — Princeton’s Gerrymandering Project, The Guardian, and many state reporters — document clear state‑level benefits to the party in control of redistricting and highlight concrete seat gains in specific cycles [6] [4] [1]. Both viewpoints use different metrics: national seat‑vote parity vs. granular, state‑by‑state seat outcomes.
7. What to watch going forward: law, politics, and measurement
Expect continued state fights: state courts, ballot measures (California Proposition 50), mid‑decade map moves, and new PlanScore/ensemble analyses will shape who benefits; litigation over racial gerrymandering and changing state constitutional rules will also be decisive [8] [10] [5]. Observers should track seat simulations and court rulings rather than rely on a single national headline: available reporting shows state variation is the rule, not the exception [9] [4].
Limitations and transparency note: This summary synthesizes recent reporting and analytic projects; available sources do not provide a single, definitive 50‑year state‑by‑state ledger of who benefited most in every redistricting cycle — instead they offer state case studies, national analyses with differing conclusions, and real‑time litigation updates [6] [4] [9].