Changes in state legislative chamber partisan control, 1992-present
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Between 1992 and 2026, 160 changes in partisan control occurred in state legislative chambers across the country. This page analyzes how often state legislative chambers changed partisan control together (both chambers changed control simultaneously) and separately (one chamber changed control). While chambers may have periodic split control, especially chambers with an even number of seats, this page includes only complete transfers of power from one major party to the other.[1]
On this page, you will find:
- An overview of state legislative chamber control changes between 1992 and 2026
- Information about state legislative chambers that changed control simultaneously
- Information about state legislative chambers that changed independently
Overview
Between 1992 and 2026, there were 160 total changes in partisan control across the nation's 99 state legislative chambers. That included 78 total changes in lower chamber control and 82 total changes in upper chamber control. Seven years produced 10 or more changes in chamber control. Most recently, ten legislative chambers changed partisan control in 2014—five upper chambers and five lower chambers.
Simultaneous control changes
Between 1992 and 2026, both of a state's legislative chambers changed partisan control during the same year 20 times—11 times from Democratic to Republican control and eight times from Republican to Democratic control. One time, in Vermont in 1992, the senate changed from Democratic to Republican control while the house changed from Republican to Democratic control.
The most instances occurred in 2010, when six states saw both legislative chambers change from Democratic to Republican control. The Washington Time's Joseph Weber wrote at the time, "The Republican midterm wave swept through state capitals across the nation Tuesday, with historic gains in state legislative races that will give the GOP a major advantage in influencing congressional races over the next 10 years through redistricting."[2] Republicans gained control of 22 chambers formerly controlled by Democrats that year.
Three states—Maine, Minnesota, and Nevada—had both state legislative chambers change partisan control twice between 1992 and 2026. One state—New Hampshire—had both state legislative chambers change partisan control four times between 1992 and 2026.
By state
Individual changes
Between 1992 and 2026, single state legislative chambers changed partisan control 120 times. Those are instances where only a state's upper or lower chamber changed control, while the other chamber's control remained the same. While the vast majority of changes in partisan control occurred as a result of regularly scheduled elections, a few occurred following changes in officeholders' party affiliations or as a result of special elections.
Six states—Colorado, Minnesota, Pennsylvania, Virginia, Washington, and Wisconsin—had more than five elections result in a state legislative chamber changing partisan control. Washington and Wisconsin had the most changes in chamber control with eight. Twelve states had no legislative chambers change partisan control.[3]
By state
See also
Footnotes
- ↑ A change from split control to Republican control or from Democratic control to split control would not be included, for example.
- ↑ The Washington Times, "Statehouse wins put GOP in redistricting driver’s seat," November 3, 2010
- ↑ Nebraska's officially non-partisan legislature was omitted.
