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Monday, October 30, 2023


Understanding the Partisan Divide: How Demographics and Policy Views Shape Political Party Coalitions 

 GUEST BLOG / By Oscar Pocasangre and Lee Drutman with New America, a think tank dedicated to a vision of a more equitable America that lives up to its values. 

 Executive Summary 

To win congressional majorities, Democratic and Republican parties must stitch together coalitions that are broad enough to accommodate their stronghold districts and swing districts, but distinct enough to differentiate themselves from each other. 

How each party builds these coalitions depends, in part, on the demographic characteristics and policy views of voters in districts where they garner most support and how these overlap with voters in competitive districts. 

In this report, we show how Democratic and Republican districts differ from each other and where they overlap with competitive districts. 

Democratic districts tend to be more affluent and more diverse than Republican districts, which are mostly poorer and predominantly white. 

Competitive districts comprise roughly equal shares of districts that are more and less affluent than the district average, but they tend to be whiter than the average district. The winner-take-all electoral system accentuates these differences and reduces the diverse constellation of districts to a binary. 

This results in an inadequate representation of voters in districts that are far from the median Democratic or Republican district. 

Key Takeaways 

• Democratic and Republican districts differ in important ways on demographic variables and policy views. Our winner-take-all system reduces these differences to a binary, hiding the diversity of districts and possible areas of overlap. 

• Republican districts are some of the least ethnically diverse districts. But voters within these districts have diverse policy views, particularly on economic issues.

• Democratic districts are some of the most ethnically diverse districts. But voters within these districts are mostly in agreement over their views of both social and economic issues. 

• Competitive districts include roughly equal numbers of ethnically diverse and ethnically homogeneous districts. While they lean towards the conservative side on many social and economic issues, voters in competitive districts have a wide mix of policy views. 

• Parties need to distinguish themselves from each other as much as possible in a winner-take-all system to make inroads in competitive districts. This encourages them to stitch together coalitions that emphasize their demographic and policy differences.

Republicans do so by appealing to rich and poor white voters with cultural and identity issues with questions of identity: “Who are we and where are we headed?” 

Democrats do so by appealing to an ethnically diverse electorate with clearer policy offerings, asking: “Who gets what and how much?” 


Decades of polarization and partisan sorting, along with a growing urban-rural divide, have created different partisan strongholds for Democrat and Republican parties across the United States. 

The distinctions between the congressional districts represented by Republicans and those represented by Democrats lead to different strategies in how each party maintains support among their core constituencies while simultaneously trying to make inroads in those few competitive districts that ultimately decide which party controls the House. 

In this report, we use a combination of Census and survey data to show how congressional districts represented by Republicans differ from those represented by Democrats in terms of demographic characteristics, levels of ethnic diversity, and the policy views of voters in those districts. 

We also show how these partisan districts differ from competitive districts, which although few in number, play an outsized role in the country’s winner-take-all elections. 

Exploring the differences in demographics and policy preferences across Democratic, Republican, and competitive districts provides insights that help explain current dynamics within parties. It also sheds light on the policies that parties emphasize in their efforts to build broader coalitions that capture voters in competitive districts. 

While our analysis reveals important differences between Democratic and Republican districts, it also shows that these differences are not clear-cut and that districts fall along a continuum of demographic characteristics and policy views. 

The two-party system hides this diversity while exaggerating differences, precluding the emergence of new coalitions where different types of districts overlap. As expected, we find that Republican districts are predominantly white and, for the most part, less affluent than the national average. 

In contrast, Democratic districts are less white than the average but tend to be more affluent than average. 

Republican districts are also some of the least diverse in terms of their ethnic composition while Democratic districts tend to be more diverse than the national average. 

Competitive districts are in the middle. They are more affluent than Republican districts but less so than Democratic districts. Competitive districts tend to be whiter than the average and whiter than Democratic districts, but not as white as Republican districts. 

When it comes to ethnic diversity, competitive districts are roughly split, with about half of competitive districts below the national average of the diversity index we estimate and the other half above. 

Having a relatively homogenous group of constituents in its stronghold districts and facing competitive districts with a higher share of its population that is white, the Republican party might have an easier time appealing to voters across these districts with identity-based or cultural issues. 

The Democratic party is forced to pitch a bigger tent to accommodate the diversity of ethnic groups within its districts, which may create challenges in making inroads in competitive districts. On policy views, however, residents in Democratic districts exhibit greater agreement than their counterparts in competitive or Republican districts. 

Democratic districts are internally quite homogeneous in their policy views of both social and economic issues, but across districts they exhibit a diverse set of viewpoints. 

On the other hand, Republican districts have higher levels of ideological heterogeneity internally, particularly when it comes to views of economic issues, but exhibit little diversity across districts. 

In competitive districts, we observe some of the highest levels of heterogeneity in the policy views of citizens, which reflects the mix of partisans that coexist within competitive districts. This mix likely stems from the predominantly suburban location of competitive districts, which given the political geography of the country makes it more likely that they have a more balanced share of partisans than the Republican countryside or the Democratic metropolis. 

As pointed out by scholars of political geography and polarization, the diversity of policy preferences in competitive districts makes it tricky for parties to identify the policy views of voters who could be persuaded—as we show in a previous report on undecided voters—leading parties to mobilize their core voters in competitive districts instead. 

For the Republican party, the combination of ideologically diverse competitive districts and the assortment of views on economic issues in its stronghold districts can make it challenging to present a platform on economic issues that appeals to all its voters. This makes identity and cultural issues more appealing in campaigns, especially given the ethnic homogeneity of Republican districts and encourages Republicans to mobilize core constituents instead of focusing too much on policy issues. 

In fact, in 2020, the party didn't even offer a formal policy platform. While the Republican coalition is kept together by exploiting questions of identity (“Who are we?” and “Where are we headed?”), the Democratic coalition is held together by questions of distribution (“Who gets what, and how much?”). 

Politicians in Democratic districts are better able to identify the policies their constituents want, but there is a wider range of policy views across Democratic districts. 

In a more permissive electoral system, the diverse collection of views would result in different parties—one for the likes of President Joe Biden and another for the likes of Rep. Alexandria Ocasio-Cortez (D-N.Y.)—but the two-party system and the intense opposition to Republican positions keeps the Democratic coalition together. 

The Democratic and Republican parties find their strongholds in districts that, on average, are very different. Democrats get most of their votes from ethnically diverse districts but with constituents that, for the most part, are in agreement over policy issues. 

Republicans get their votes from predominantly white districts but with constituents that disagree more on policy matters, particularly on economic issues. But, increasingly, neither party can win a majority in Congress without winning competitive districts and have to find ways to win over voters in these districts, with the comfort that the combination of winner-take-all and intense negative partisanship and polarization will prevent mass defections from their stronghold districts. 

The gravitational pull of a small number of competitive districts in the American electoral system—much like that of undecided voters—reflects the calcification of national politics. But beneath this calcification, our report shows that there is fertile ground for new coalitions to emerge given the diversity in demographics and policy views exhibited by districts. 

More permissive electoral rules, like proportional representation, would allow these coalitions to crack through our calcified system and provide better representation to voters in districts that do not fit comfortably in the existing party tents or whose views are completely unrepresented because they live in partisan strongholds. 

About the Data 

The classification of districts into Democratic, Republican, or competitive comes from the ratings of the Cook Political Report for the 2020 and 2022 midterm elections. Competitive districts are those classified as toss ups for each cycle while the partisan districts are those rated as solid, likely, or lean Democratic or 

Republican. Demographic data comes from the 2020 census and from the 5-year estimates of the American Community Survey (ACS) for 2020. Between 2020 and 2022, congressional districts were redistricted, so we approximate the new congressional maps for the 2022 midterms using the block equivalency files provided by each state to the Census Bureau. 

These files allow us to match each census block to its new congressional district. The data on policy views comes from the Democracy Fund and UCLA Nationscape survey, aggregated to the district level. The survey carried out 77 waves from July 2019 through January 2021 and reached almost 500,000 respondents. We use the same dataset for our report on undecided voters, for which we created indices for various social and economic issues. 

On the social dimension, the issues are abortion, gun control, immigration, views on structural discrimination, and traditional and Christian values and positions. On the economic side, the issues are environmental protections and investments, debt free college, government role in healthcare, government role in the economy, and taxation. 


What distinguishes Democratic, Republican, and competitive districts from each other? In this section, we provide a description of demographic characteristics of these districts, for both 2020 and for 2022, after the redistricting process. Polarization and partisan sorting has created a mega-identity composed of reinforcing racial, ethnic, and other social identities. 

Because of this, the basic demographic breakdown of congressional districts can be informative for understanding the different effects these districts have on Democrats and Republicans. Figure 1 shows the distribution of districts based on the shares of their white population and their average household income. 

Districts in the upper quadrants are, on average, richer than average and those in the right-side quadrants have shares of white residents higher than the district average. As seen in the figure, most Republican districts clustered in the lower right quadrant in 2020: 71 percent of Republican districts were whiter than the national average and had lower than average household incomes. 

For the most part, the Republican districts that had shares of white residents below the average were districts with high shares of Hispanic residents, like those in states like California, Florida, and Texas. 

Democratic districts were scattered all over the other quadrants, with 57 percent of Democratic districts in high income groups. Of these higher income districts, 58 percent were below the national average of white residents and 42 percent above. 

Meanwhile, 31 percent of the all Democratic districts were both poorer and less white than the national average and only 12 percent were poorer but whiter than the national average. 

Competitive districts were whiter than the average congressional district. In this characteristic, they overlap with reliably Republican districts. But unlike Republican districts, there were roughly equal numbers of competitive districts above the average household income level as there were below. Such conditions create opportunities for Republicans to exploit identity and cultural issues instead of economic issues. 

Politicians always seek issues that cut across multiple groups in society to create a broad coalition that can be mobilized to the polls. 

For Republicans, then, it is better to build a coalition around issues of identity and race because they appeal to lower- and higher-income white voters in both competitive and Republican districts instead of campaigning on economic issues which would pit lower-income Republicans who support progressive economic policies against higher-income Republicans who do not. 

Following the redistricting process, which was done with new census data from 2020, little changed in terms of the income and ethnic composition of districts. For the 2022 midterms, we observe a similar distribution of Republican and Democratic districts across household income levels and shares of white residents. 

Again, most competitive districts had shares of white voters higher than the national district average. And like in 2020, there were equal numbers of competitive districts below and above the average income across the districts. 

Another important demographic characteristic is how diverse congressional districts are internally in terms of their ethnic composition. To explore diversity within districts, we calculate the Herfindahl-Hirschman Index for each congressional district using the shares of the population that identify as white, Black, Hispanic, Asian, or other. This index is a widely used measure of diversity where zero (“0”) indicates that there is only one ethnic group present while 10 indicates that each ethnic group has equal shares of the population within each district. 

The Herfindahl-Hirschman Index shows that most Republican districts are among the least ethnically diverse while Democratic districts are the most ethnically diverse. In 2022, of all the Republican districts, 61 percent of them were below the national average of the diversity index, with high shares of white residents resulting in low levels of diversity. 

In contrast, 83 percent of Democratic districts were above the national average of the diversity index in 2022, which underscores the diverse coalition across ethnic groups that the Democratic party has to keep together. 

Competitive districts were in the middle: Of the 36 competitive districts in 2022, 19 were below the national average of the diversity index while 17 were above the average. Most of the diversity in the Republican party comes from larger Hispanic populations in Texas and Florida. 

Of the 83 Republican districts that had scored a diversity index higher than the national average, 29 percent of these districts were in Texas, followed by 12 percent in Florida. Florida also has the most Republican districts with the least diversity: 8 percent of Republican districts with diversity indices below the national average were located in that state, another 8 percent is located in Ohio. 

For Democrats, a quarter of the districts that were above the national average in the diversity index were located in California, followed by nine percent in New York. Of the Democratic districts with below average diversity indices, 15 percent were in Massachusetts followed by 12 percent in Michigan. 


 American politics today is often described as “calcified,” a reference to two sides being pitted rigidly against one another. It's a useful description— coined by John Sides, Chris Tausanovitch, and Lynn Vavreck—to characterize how voters have been shuffled into two distinctly, and firmly, different parties. 

Calcification has created different types of congressional districts for Democrats and Republicans to represent. As we show in the report, Democrats garner most of their support from urban districts that are more affluent and more ethnically diverse, while Republicans mostly do so from districts that are rural, less affluent, and predominantly white. 

Democratic districts are mostly progressive on both social and economic policy issues, while Republicans are mostly conservative. 

The winner-take-all electoral system magnifies this distinction, creating binary choices for voters and forcing parties to differentiate themselves from each other as much as possible. 

But our analysis indicates that the differences between Democratic and Republican districts are not as clear-cut. There are affluent Republican districts and there are poor Democratic districts, there are Republican districts that have progressive views on social and economic policy issues and Democratic districts that lean conservative on these issues. Congressional districts—and the voters within them—exist in a continuum of demographic characteristics and hold a variety of policy views. 

This suggests that there could be many and more diverse political coalitions if the electoral system were more permissive and proportional. Democratic and Republican districts do differ on average on various demographic variables and they tend to gravitate towards opposite ends of the policy spectrum. 

But it is the winner-take-all, two-party system that exaggerates these differences and turns them into a binary, preventing the discovery of common ground and the emergence of new parties that could better represent voters in districts that are far from the median ideological points of each party. 

Each party will be able to maximize its seats by choosing policies closest to where the majority of districts fall, but that leaves many districts inadequately represented. The lack of political options reduces all of the country’s ethnic and ideological diversity to a choice of us versus them. 

Recent elections have shown that voters in partisan strongholds continue voting for their parties—indeed very few incumbents lost elections in the 2022 midterms—and that any shifts in the balance of power comes from swaying swing districts towards one side or the other. To do so, the Republican party has taken the strategy of emphasizing identity issues—crime, immigration, gender—that stoke fear among their predominantly white stronghold districts and that have a better chance of appealing to the majorities of white voters in competitive districts and to their core voters in those districts. 

The focus on identity and cultural issues leaves less room for compromising and fewer opportunities to develop cohesive programmatic policy platforms. Democrats, for their part, have to build broad coalitions that include various ethnic groups and an assortment of better defined policy positions, which makes it difficult for them to exploit identity and cultural issues—other than by highlighting threats from Republicans—but easier for them to negotiate over policy concessions. Under these conditions, the hyper-polarization that characterizes American politics becomes increasingly difficult to resolve. 

The different ways in which Democrats and Republicans carve out and sustain their respective coalitions leaves little room for agreement, particularly when identity and cultural issues replace economic issues as the focal conflict of politics. Multi-party democracy would help mitigate polarization by relegating extreme views to fringe parties as it empowers new coalitions to emerge around other issues. 


Oscar Pocasangre 

Lee Drutman 



The authors thank Mark Schmitt and Maresa Strano for helpful comments and editing support. Thank you also to Jodi Narde, Joe Wilkes, and Naomi Morduch Toubman for their graphics and communications support. Funding for this work was provided by the Hewlett Foundation and Democracy Fund. All positions are those solely of the authors. 

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