The Polarized Partisan Geography of Inequality

Democrats represent some of the richest House districts—but they're also more likely to have deeply unequal constituencies. Is that why the party is more focused on income disparities?

Few issues these days set Democrats apart from Republicans more than income inequality, and the Democratic leadership has made it a signature issue. Can we trace back some of the divergence to the surprising fact that Democrats—especially senior Democrats—represent the districts with the most inequality?

A few days ago, the Associated Press ran a short piece noting, “Of the 10 richest House districts, only two have Republican congressmen.” Later in the piece, the reporter, Stephen Ohlemacher, noted that although Democrats represent many of the richest districts, the overall difference in per-capita income between Democratic and Republican districts “is relatively small because Democrats also represent a lot of poor districts, putting the average in the middle.”

That alone might lead us to draw a reasonable conclusion about the party leadership’s focus on income inequality: If their caucus is made up of members who disproportionately represent the poorest and richest districts, Democratic leaders—taking a bird’s-eye view of the party’s overall constituent base—might be quicker to recognize the yawning gap between the rich and poor than their Republican counterparts. The Democratic rank-and-file, comparing districts, could reason the same among themselves.

But while we know there is income inequality across the party’s districts, is there also inequality within the party’s districts?

Thanks to the U.S. Census Bureau’s tabulation of the Gini indices for each congressional district, we can answer that question. Here is what the distribution looks like:

(Full data are at the bottom of this post.)

As the data show, Democrats have a lock not only on the country’s richest districts but also on the districts with the highest in-district income inequality.

Democratic Representatives Carolyn Maloney (N.Y.-12) and Chaka Fattah (Pa.-02) illustrate the distinction between the richest and the most unequal districts.

Maloney’s seat topped the AP’s list of wealthiest districts. Per-capita income in the New York 12th comes out to $75,479, or “more than $75,000 a year for every man, woman and child,” as the AP put it. The median household income in Maloney’s district, meanwhile, is a cool $82,823 (21st of all the districts), but it doesn’t compare to the mean household income, which is $142,577 (first of all the districts). In other words, there are a small number of super-rich people in Maloney’s district pulling up the household average. And that’s what the Gini index reports, too: Her district has the third-highest income inequality, which is understandable, since it doesn’t just include the Manhattan’s Upper East Side, but also less tony neighborhoods like Queens’s Long Island City and Brooklyn’s Greenpoint.

Fattah, on the other hand, doesn’t come close to showing up on the list of rich districts—per-capita income in his district is $25,564, just over a third of what it is in Maloney’s. Again, however, there’s a sizable gap between the median household income ($34,897) and the mean household income ($61,718)—which reflects the fact that Fattah doesn’t just represent economically depressed West Philadelphia but also affluent neighborhoods like Chestnut Hill that are right next door. Fattah’s district is even more vertiginously unequal than Maloney’s—it’s the second most unequal in the nation. (First place goes to Representative Jerrold Nadler from the N.Y.-10, which includes both Manhattan’s Upper West Side, and neighborhoods in Brooklyn like Red Hook, Bensonhurst, and Borough Park. Minority Leader Nancy Pelosi’s San Francisco district is the 16th most unequal.)

Both Maloney’s and Fattah’s districts are deep blue (the Cook Partisan Voting Index for each is greater than D+25), and both reflect two intertwined trends: cities have become, in general, strongholds of the Democratic Party, and cities have become, in general, hives of the most dramatic income inequality in the country.

Considered alongside these well-established trends, the fact that Democrats represent districts that are (on average) more unequal than Republican districts suggests that the parties may have such divergent views on income inequality in part because their members (and constituents) have divergent experiences of income inequality. Could polarization, in other words, be driven by the availability heuristic?

The availability heuristic is a psychological term that describes the human tendency to estimate the frequency of an event by using the examples that come most readily to mind. As psychologist Daniel Kahneman—who coined the term with his research partner, Amos Tversky—recalls in Thinking, Fast and Slow:

Amos and I wondered about the rate of divorce among professors in our university. We noticed that the question triggered a search of memory for divorced professors we knew or knew about, and that we judged the size of the categories by the ease with which instances came to mind. We called this reliance on the ease of memory search the availability heuristic.

The availability heuristic (or availability bias), Kahneman notes, is what causes people to estimate that tornadoes kill more people than asthma, even though dying from asthma is 20 times more likely. Because we hear and read vivid stories about tornado deaths in the media—and virtually none about asthma deaths—we assume that tornado deaths are more common.

It’s not impossible to imagine this effect playing out in Congress. Given that Maloney and Fattah regularly pass between some of the richest and poorest neighborhoods in America within a few minutes, it’s not shocking that they might see income inequality as a bigger problem than, say, Republican Representative Michele Bachmann (Minn.-06), a staunch conservative who (perhaps ironically) represents the district with the least income inequality in America (Gini index of 0.385). Likewise, it’s not impossible to imagine that Maloney’s and Fattah’s constituents—who look across the street at people with wildly different incomes than their own—think of income inequality as a bigger deal than Bachmann’s constituents do.

Consider the partisan make-up of the 25 congressional districts with the highest levels of income inequality versus the 25 lowest:

While Republicans don’t dominate the least unequal districts to the degree Democrats dominate the most unequal, they do have an edge.

Moreover, not all members of Congress have equal say in their party’s messaging and issue stances. When we strip out all but the 100 most senior members of the House from the original distribution, the effect becomes similarly pronounced:

That is, the most senior Democrats in Congress—and their constituents—seem to have far more direct experience with income inequality than the most senior Republicans in Congress. It’s not surprising that they see the issues differently.

None of this is to say that income inequality isn’t a big problem. I believe it is. But then again, I live in the Massachusetts 5th, the 74th most unequal congressional district in the country. It’s no wonder I’m more alive to the problem than a resident of Bachmann’s Minnesota 6th, which comes in 436th place (D.C. included).

For years, one of the most interesting charts in American politics has been the graph showing how closely political polarization and income inequality in America track one another (copied here, courtesy of Christopher Hare, Keith Poole, and Howard Rosenthal’s Voteview blog):

The fact that Democratic and Republican members of Congress represent districts that encompass significantly varying levels of income inequality doesn’t solve that mystery, and we shouldn’t confuse correlation for causation. But the trend raises hypotheses we might test. For example, Jacob Jensen, Suresh Naidu, Ethan Kaplan, and Laurence Wilse-Samson wrote a methodologically fascinating paper for the Brookings Papers on Economic Activity in 2012 in which they analyzed the text of the Congressional Record and Google Books corpus, identifying the most partisan phrases and using them to explore political polarization and legislative gridlock. It would be fascinating to use their “text-as-data” approach to explore whether Democrats or Republicans from the most unequal districts talk about income inequality more than their same-party colleagues representing the least unequal districts. Likewise, one might look at how constituent polling on the importance of income inequality as an issue compares between the highest and lowest inequality districts.

The parties have long seen the income-inequality issue differently in ideological terms. We should learn more about the degree to which they see it differently in plain old empirical terms.