When Democratic leaders escaped Texas to halt the Republican-controlled Legislature from redrawing congressional district lines, it was the latest instance in a long-standing history of gerrymandering in the United States.

The term “gerrymander” originated in America over two centuries ago, used to describe the manipulative creation of legislative districts for political gain.

The word has stood the test of time, in part, because American politics has remained fiercely competitive.

Who is responsible for gerrymandering?

In several states, including Texas, responsibility for drawing congressional districts lies with the state legislature, subject to the governor’s approval or veto. These district maps must be revised every decade following the census to ensure population balance within the districts.

But in some states, nothing prevents legislatures from conducting redistricting more often.

To reduce gerrymandering, certain states have assigned the redistricting task to special commissions made up of citizens or bipartisan political panels. Now, Democratic officials in some states that employ these commissions are considering ways to bypass them, aiming to counteract the Republican redistricting efforts observed in Texas.

How does a gerrymander work?

If one political party holds control over both the legislature and the governor’s office—or commands a legislative majority large enough to overturn vetoes—it can shape districts to its benefit.

A typical gerrymandering strategy involves the dominant party drawing district maps that cluster opposing party supporters into a handful of districts, thereby increasing the dominant party’s chances to secure more adjacent districts.

Another common method is for the majority party to dilute the power of an opposing party’s voters by spreading them among multiple districts.

Why is it called gerrymandering?

The term dates to 1812, when Massachusetts Gov. Elbridge Gerry signed a bill redrawing state Senate districts to benefit the Democratic-Republican Party. Some thought an oddly shaped district looked like a salamander. A newspaper illustration dubbed it “The Gerry-mander” — a term that later came to describe any district drawn for political advantage. Gerry lost re-election as governor in 1812 but won election that same year as vice president with President James Madison.

Is political gerrymandering illegal?

Not under the U.S. Constitution. The Supreme Court, in a 2019 case originating from North Carolina, ruled that federal courts have no authority to decide whether partisan gerrymandering goes too far. Chief Justice John Roberts wrote: “The Constitution supplies no objective measure for assessing whether a districting map treats a political party fairly.”

The Supreme Court noted that partisan gerrymandering claims could continue to be decided in state courts under their own constitutions and laws. But some state courts, including North Carolina’s highest court, have ruled that they also have no authority to decide partisan gerrymandering claims.

Are there any limits on redistricting?

Yes. Though it’s difficult to challenge legislative districts on political grounds, the Supreme Court has upheld challenges on racial grounds. In a 2023 case from Alabama, the high court said the congressional districts drawn by the state’s Republican-led Legislature likely violated the Voting Rights Act by diluting the voting strength of Black residents. The court let a similar claim proceed in Louisiana. Both states subsequently redrew their districts.

What does data show about gerrymandering?

Statisticians and political scientists have developed a variety of ways to try to quantify the partisan advantage that may be attributable to gerrymandering.

Republicans, who control redistricting in more states than Democrats, used the 2010 census data to create a strong gerrymander. An Associated Press analysis of that decade’s redistricting found that Republicans enjoyed a greater political advantage in more states than either party had in the past 50 years.

But Democrats responded to match Republican gerrymandering after the 2020 census. The adoption of redistricting commissions also limited gerrymandering in some states. An AP analysis of the 2022 elections — the first under new maps — found that Republicans won just one more U.S. House seat than would have been expected based on the average share of the vote they received nationwide. That was one of the most politically balanced outcomes in years.