Short-term advancements in data science combined with long-term shifts in how Americans vote are making swing districts increasingly rare.
State legislatures and political commissions control the redistricting process for the majority of the country. So far, 20 states have finished redrawing their congressional maps, which have produced only a handful of competitive House seats.
“It is almost a survival strategy for political parties within the states,” said Ken Kollman, a political science professor at the University of Michigan. “Competitive districts might be in someone’s interest — it might be in the interest of the public, it might be in the interest of our democracy, it might be in the interest of moderate policies moving forward — but it’s not in the interests of the specific state political parties.”
Political parties burned by recent wave elections — like Republicans in 2018 when Democrats took control of the House — may have gotten skittish about drawing risky seats. Kollman said a House map with many competitive seats would mean a party could win a few from the other side, or totally wipe out.
Months away from the first primary elections, it appears more House races will unfold in districts where one party holds a significant advantage. Although many campaigns to establish independent commissions have emphasized the need to create more competitive elections, it’s not always that easy.
Redistricting expert Kim Brace, who served as a consultant for Michigan’s redistricting commission, said that state’s process ran into problems when trying to satisfy competing priorities, such as complying with the Voting Rights Act — which can require drawing less competitive districts — and creating “compact” districts that split as few communities as possible. The state commission has several drafts and intends to approve a final plan later this month.
After going through that, competitiveness may fall to the wayside, Brace said; the commission’s three draft maps for Michigan have two or three competitive seats each, out of 13 total. Iowa, another commission state, produced a map under which the presidential margins in three of its four seats would have been less than 5 points.
As state legislatures continue to draw maps this cycle, the stakes are high for a closely divided House. The maps could end up determining control of the chamber, according to James Gimpel, a political science professor at the University of Maryland.
“Even if all of redistricting makes a 12- or 15-seat difference, it could be the size of your majority,” Gimpel said.
That means the parties that control the legislatures drawing the maps want to make sure they gain or keep as many seats as possible, said Michael Li, senior counsel for the Brennan Center for Justice at the New York University School of Law.
Republicans, who made major gains in statehouses in a 2010 wave election that netted them 63 U.S. House seats, are now looking to maintain their advantages rather than go for new seats, Li said. GOP legislatures control redistricting in 19 states compared to eight for Democrats. The rest are either split or controlled by commissions.
“This decade people are doing gerrymanders, but they’re doing more ‘circling-the-wagons’ gerrymanders,” Li said.
Some states where Democrats control redistricting, such as Maryland, Illinois and Oregon, have produced maps with Democrat-leaning competitive seats. Such maps are targeting Republican incumbents, like Maryland’s Andy Harris, or forcing intraparty primaries. For example, after Illinois lost a seat following the 2020 census, Democratic mapmakers combined two Republican districts, essentially packing GOP voters into a single seat.
Li said Illinois and other states controlled by Democrats are aggressively drawing congressional maps, going after Republican-held seats. However, the parsurty may have created a “booby trap” by drawing slightly Democratic districts that could swing red in a strong year for the GOP, Li said.
Those trends have also surfaced as political data has exploded in the past decade, according to Kollman. Political data firms have massive and growing voter files that include voting history, activity, language, ethnicity and religious affiliation.
“The data science revolution hitting American electoral politics has led to very careful engineering so they can pretty much know how we’re going to vote, pretty much at the level of neighborhood and ZIP code. You can be very precise, more than in the past,” Kollman said.
Though people want more competitive House districts, it’s harder to draw them in ways that make sense.
Political homogeneity in many communities has grown over the past several decades. Individual geographical areas are more likely to vote for one party over another, as local communities grow increasingly homogeneous along income and education lines, according to a 2017 paper from researchers at MIT.
Gimpel said that means any underlying goals of redistricting — such as preserving communities of interest and making districts as compact as possible — will trend toward drawing a seat with constituents who vote similarly.
“If you are going to draw a boundary around a community of interest, you are drawing a boundary around a district that is going to vote one way or another,” hesaid. “These folks often share values, including political values, and that is now part of what a community means.”
While cities have gotten more Democratic and rural areas more Republican, the suburbs of major cities, such as Atlanta, Chicago and Dallas, have gotten more competitive.
Even as places like suburban Chicago diversify, trying to draw competitive districts there runs up against other redistricting priorities, such as complying with the Voting Rights Act, Brace said. To maintain the percentage of Black voters in Illinois’ 1st and 2nd districts, the state’s new map included more of the Chicago suburbs than ever.
In some cases, mapmakers have targeted those areas. Li said Republicans redrew districts around Atlanta and Texas’ major cities to remove competition over suburban territory.
In Texas and Georgia, that would mean safer seats for both sides, but a net gain for Republicans, Li said. Both states currently face federal lawsuits alleging they violated the Voting Rights Act in drawing those lines.
“Republicans are betting that with a narrow Democratic majority in the House, if they can hang on to what they have and just rely on the dynamics of the year to pick up a few seats here and there … that’s enough to give them a decent shot at a majority — potentially a majority for the whole of the decade,” Li said.