Death knell for Republicans in Illinois’s 6th congressional district?

Democrat Sean Casten unseated Republican incumbent Peter Roskam in a House race in the 6th Congressional District in Illinois. Does this signal the end of Republican dominance in this suburban district? Some points to consider:

  1. This has been a Republican district since the early 1970s. Before that, the District was represented by a Democrat since the late 1920s and dominated by Republicans between the Civil War and 1911. Long-time representative Henry Hyde passing the seat to Peter Roskam may be the recent history but the district has more variation over the years.
  2. The demographics of these suburban areas has changed quite a bit. Like many American suburbs, the Chicago suburbs have become increasingly non-white and more diverse in terms of social class. The area covered by the district today is not the same white, middle-class swath that it may have once appeared to be.
  3. Redistricting and changing boundaries has happened with the 6th in the past and could happen again in the future. Read more about Illinois redistricting efforts in the 1970s and early 2000s. Some background on this particular district:

Roskam replaced conservative icon U.S. Rep. Henry Hyde in Congress, but much of his old territory in eastern DuPage County is now represented by U.S. Reps. Mike Quigley of Chicago and Raja Krishnamoorthi of Schaumburg, both Democrats.

4. The patterns of voting in the Chicago area suburbs mirror larger trends about suburban voters. The 6th district as well as several other House districts are comprised of the middle ground between Democratic voters in the big city and close suburbs and Republican voters in more rural areas and outer suburbs. These are the battleground areas and this will likely continue in future election cycles.

All this said, there are no guarantees in this district. Multiple factors could sway voters in this district in the near and far future including changes in what the national parties stand for (and what presidential candidates are leading the way), increasing diversity in the suburbs, possible redistricting, and particular concerns and issues that may resonate voters in the middle suburbs. As the suburbs continue to be important areas for both parties to try to pick up seats, expect this district to continue to be contested for at least a few elections to come.

Computer models of the effects of gerrymandering on urban and rural voters

A new computer simulation of voting patterns by geography in the United States suggests gerrymandering may not be the cause of Republican majorities in the House:

To examine this hypothesis, we adapted a computer algorithm that we recently introduced in the Quarterly Journal of Political Science. It allows us to draw thousands of alternative, nonpartisan redistricting plans and assess the partisan advantage built into each plan. First we created a large number of districting plans (as many as 1,000) for each of 49 states. Then we predicted the probability that a Democrat or Republican would win each simulated district based on the results of the 2008 presidential election and tallied the expected Republican seats associated with each simulated plan.

The results were not encouraging for reform advocates. In the vast majority of states, our nonpartisan simulations produced Republican seat shares that were not much different from the actual numbers in the last election. This was true even in some states, like Indiana and Missouri, with heavy Republican influence over redistricting. Both of these states were hotly contested and leaned only slightly Republican over all, but of the 17 seats between them, only four were won by Democrats (in St. Louis, Kansas City, Gary and Indianapolis). While some of our simulations generated an additional Democratic seat around St. Louis or Indianapolis, most of them did not, and in any case, a vanishingly small number of simulations gave Democrats a congressional seat share commensurate with their overall support in these states.

The problem for Democrats is that they have overwhelming majorities not only in the dense, poor urban centers, but also in isolated, far-flung college towns, historical mining areas and 19th-century manufacturing towns that are surrounded by and ultimately overwhelmed by rural Republicans.

A motivated Democratic cartographer could produce districts that accurately reflected overall partisanship in states like these by carefully crafting the metropolitan districts and snaking districts along the historical canals and rail lines that once connected the nonmetropolitan Democratic enclaves. But such districts are unlikely to emerge by chance from a nonpartisan process. On the other hand, a Republican cartographer in these and other Midwestern states, along with some Southern states like Georgia and Tennessee, could do little to improve on the advantage bestowed by the existing human geography.

Perhaps this introduces a new strategy for political parties: the need to have more evenly distributed support rather than large clusters of support. But, as the bottom of the article notes, certain redistricting strategies like in Illinois or Maryland can provide Democrats some help in spreading out the effects of their urban voters.

Illinois redistricting also about capturing suburban voters

Much of the press about redistricting in Illinois has highlighted how Democrats plan to increase their seats. But the Daily Herald offers an additional insight by suggesting that the redistricting is really about capturing suburban voters:

But even as political analysts poring over the new boundaries provide slightly different takes, one thing is certain: the suburbs, which saw booming growth over the last decade, were the prime meat in the proverbial fattened calf — filleted to produce congressional districts that would help assure a Democratic majority in the state’s delegation over the next 10 years…

“There’s been a shift in power,” Northern Illinois University professor Richard Greene said. “Because of the population shift, the Democratic core and the inner manufacturing suburbs are losing strength, as the outer-edge suburban communities are gaining substantially in strength.”

Democrats, political consultant Kitty Kurth said, want to continue to capitalize on their base — the largely Democratic voting bloc of Chicago, some of which has moved to the suburbs in recent years.

The new map appears to do just that, in some cases through odd-shaped districts that often start in solidly Democratic Chicago and extend into the suburbs through long, gnarled fingers. That essentially extends Democratic Chicago districts into traditionally Republican suburban ones, but not by so much as to put any Democratic majority at risk.

Traditionally, some of the suburban areas, particularly DuPage County, have been solidly Republican strongholds. While these figures are already changing somewhat, this redistricting might help push  these state offices further away from Republicans.

The article also goes on to note how the second Hispanic district in the state could be located in the southwest suburbs “centered around Aurora and Joliet.”

Such a move to control suburban votes would go along with commentary that suggests suburban voters are critical for national political outcomes.