Mapping the Decline of the GOP in DuPage County

DuPage County has been governed by Republicans for almost as long as the party and the county have existed. As the bulwark of the GOP in the Chicago area, DuPage has been key to Republican fortunes in the Land of Lincoln. For most of its history, no Democratic Presidential candidate carried DuPage. Roosevelt lost here. When Johnson carried 44 states and more than 60% of the popular vote, DuPage voters backed Goldwater in a landslide.

Within this context, the 2008 Democratic Presidential victory in DuPage looked like an anomaly. It wasn’t.

Barack Obama was the first Democratic Presidential nominee to win DuPage County. One could be forgiven for missing this portent. A popular Illinois Senator running an uncompromisingly progressive 2008 Presidential campaign was following an unpopular Republican during an economic collapse. The wave of support for Obama did not extend down the ballot. Republicans continued to dominate elections for state and local offices in DuPage, but the decline of the GOP in the suburbs had hit a tipping point. It has not recovered.

Ten years later, DuPage County’s historic pivot from Republican to Democratic dominance is nearly complete. Trump in 2016 barely topped 1/3 of the vote, a stunning surprise for this traditional GOP stronghold, but worse was coming. Republicans lost a majority of the County Board seats on the ballot in ’18. It was the first election in the county’s history in which more voters supported the generic Democratic ballot.

Why this change happened is a question for another time. What happened is explored in the maps and analysis below.

Not so long ago, local elections in DuPage County were decided in the Republican primary. The map below shows the decline in voter participation in the GOP primaries in each township since 2010.



Primary participation is an imperfect measure of voter identity, but a sustained trend in primary participation will eventually show up in general election outcomes. Republican participation has declined in every township over the past decade. Notice that the declines are consistent, with the heaviest drop coming in places that previously had the strongest Republican lean like Oak Brook and Wheaton. This suggests a driver beyond local politics, as the popularity of the GOP in suburbs declined nationally.

Quick note on the data. It would be great to see this figure down to the precinct level. However, slight modifications in the precinct maps after the 2016 election make long-term precinct-level comparisons difficult. For longer-term analysis these maps depend on township rather than precinct data.

What has this decline meant for DuPage County in General Elections? Below is a map showing the generic party identification in each township in the ’18 election.

Generic GOP Vote by Township

per township stats

To arrive at a generic, base number, this map used the results of the State Treasurer election, a contest with little fanfare in which the outcome aligns very closely with party preference. Republicans in DuPage lost every township in 2018.

Next is a precinct-level map of the generic GOP vote in ’18. Notice that much of Elmhurst has turned blue. A couple of the wealthiest and whitest precincts of Elmhurst remain Republican, but only by tiny margins. Large portions of Naperville have also flipped.

generic by precinct

Below is a map of The Alamo, the remaining GOP super-precincts in DuPage where Republicans still poll at better than 60%.

the alamo

These precincts are mostly concentrated in three places, hyper-wealthy sections of Oak Brook, the extreme social conservative enclaves of Wheaton, and an exurban bolthole around Wayne. Fifteen years ago most of the county would have appeared on this map. Now it consists of only 54 out of 930 DuPage precincts.

For comparison, below is a map of the new Democratic super-precincts. There were 165 Democratic super-precincts in DuPage in 2018.

dem precincts

Leaving for another time the question of why this happened, what does this decline in GOP dominance mean for the party?

What we’re likely to see first is a pivot by donors. The overwhelming bulk of large-dollar local political contributions are made for access, not ideology. People and businesses who’ve been funding Republican candidates in DuPage aren’t generally motivated by the party’s stance on abortion or gun rights, they are spending money to maintain access to their elected officials. Nearly all of that funding has gone to Republicans in the past because they were the only candidates likely to win. No one needs access to the candidate who lost the election. There have been small shifts in funding toward Democrats since 2008, but that trickle should become a flood very quickly, squeezing budgets for the GOP’s local organization and candidates.

Over a longer term, the rise of Democratic power in DuPage will erode Republicans’ built-in “bench advantage,” their once-ample supply of smart, promising, younger public figures available to move up from city councils and boards into top-tier races. In the past, anyone who wanted to serve their local community in elected offices joined the Republican Party. With few exceptions, it was the only avenue for advancement. Since ’08, younger people have had some options to rise in the ranks through the Democratic Party. Now, that advantage appears to have pivoted. Civic-minded younger people will no longer assume they need to be Republicans to win elections. In fact, they may assume the opposite.

Finally, the rise of suburban Democrats is likely to create an intra-party challenge to Cook County’s state-wide dominance. Chicago and the suburbs are deeply at odds on practical issues that extend beyond party platforms. A number of Democratic legislative candidates ran on their explicit opposition to the Democratic House Speaker, a fissure that’s likely to widen as Democratic power grows in the suburbs. How that rivalry plays out will be fascinating and unpredictable.

Can Republicans reverse this slide? Maybe, but it appears unlikely in the near term. Forces pushing the GOP toward extremes on the national level have alienated educated white voters, especially women, in ways that will be hard to undo.

National Republicans don’t appear to care about losing their former strongholds in places like Orange County, the Chicago collar counties, and Philadelphia’s Main Line communities. They ignored the warnings from their own 2012 “Autopsy” report, instead choosing to double down on even more explicitly white nationalist rhetoric and partnerships. Local Republicans seem blissfully unaware of the tides pulling them out to sea. DuPage Republicans have opted for silence and patience, missing their chance to rebrand themselves in opposition to an increasingly unpopular national party.

It’s likely that the decline of GOP power in DuPage will continue. The party’s core will continue to shrink into smaller and smaller pockets of the County’s oldest, wealthiest and whitest communities. A century and a half of Republican dominance in DuPage County appears to have ended.

Special thanks to Splunk for the free data analytics software and the DuPage County Election Commission for election data.

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