Our latest book is titled Divided We Stand: The 2020 Elections and American Politics. Among other things, it discusses state and congressional elections.
Mike Johnson blames gerrymandering for the Republicans' failure to win more seats in 2024. In fact, their seat share matches their vote share.
Jonathan Cervas, assistant teaching professor in political science at Carnegie Mellon who was a nonpartisan consultant on redistricting in Pennsylvania, Wisconsin and New York, told us in an email that he agreed with Niven and the Brennan Center’s findings. While “the net effect of gerrymandering is difficult to gauge,” partisan redistricting “created a substantial advantage for Republicans nationwide,” making it “pretty clear that the Republicans have the advantage in terms of how the districts lines were drawn to favor a party,” he said.
Cervas, Nevin, and the Brennan Center’s report all pointed to North Carolina as an example of partisan gerrymandering affecting the 2024 election. In 2023, the state Supreme Court reversed an earlier ruling that had prevented the implementation of a Republican-drawn map in the 2022 election, with the court now concluding that they could not rule on cases concerning partisan redistricting. As a result, the Republican-controlled state legislature redistricted the state to favor their party. In what Cervas termed “textbook gerrymandering,” the Democrats lost three congressional seats in North Carolina between 2022 and 2024 under the newly drawn map, despite what he says were similar statewide Democratic vote shares in both elections.
However, Cervas also argued that the Republican advantage through gerrymandering has decreased in recent election cycles. The “Great Gerrymander of 2012,” as experts called it, created significant partisan advantages for Republicans in the aftermath of the 2010 census. But Cervas told us that shifting political control and interventions to courts and independent commissions have lessened the Republican Party’s advantage in recent election cycles. For example, Niven and Cervas both said that recent court rulings enforcing redistricting changes in Alabama and Louisiana favored Democrats over Republicans.
Alternatively, other experts used differing methodologies to quantify the effects of gerrymandering and found a smaller net effect from partisan redistricting.
In a 2023 study, Kosuke Imai, professor of government and statistics at Harvard University and the leader of the Algorithm-Assisted Redistricting Methodology Project, found — along with his team — that Republicans possess a net advantage of only two congressional seats from partisan gerrymandering.
Similar to Cervas, Imai told us in an email that partisan redistricting efforts largely favored Republicans over Democrats after the 2010 census. However, he said that “in the 2020 redistricting cycle, some states had a partisan bias toward Democrats. As a result, even though there was widespread gerrymandering in 2020, the partisan biases were mostly canceled out at the national level.”
