Legislature Trends & Analytics
Historical chamber control, seat trends, and supermajority analysis
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D Chambers (2025)
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R Chambers (2025)
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Net Shift
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Split Legislatures
Chamber Control Over Time
Number of chambers controlled by each party. Pre-2021 data excludes split-legislature states (where individual chamber control requires research).
Total Seats by Party
Aggregate number of D and R seats across all 99 chambers (seat-count data available from 2021).
Chamber Flips by Cycle
Chambers that changed party control between snapshots.
Veto-Override Supermajorities
Chambers where one party holds enough seats to override the governor's veto.
| State | Chamber | Control | Seats | Threshold | Margin |
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Closest Margins of Control
The 15 chambers with the smallest margin above the majority threshold.
| State | Chamber | Control | D | R | Majority | Margin |
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