What Happened in the Iowa Gubernatorial Election? (2018)

Please note: The analysis below is based on an initial estimate of the 2018 electorate. Catalist released an updated analysis of the 2018 electorate in May 2019.


January 17, 2019

Author: Maggie Dart-Padover, Analyst

  1. Solidifying support among historically-reliable Democratic voters
  2. Winning middle partisans (people who are more likely to be Independent voters)
  3. Making up ground with groups of voters that swung Republican since Obama’s victories, including rural voters and voters without college degrees

Young voters (those ages 18–29) are often another vital element of the traditionally-Democratic voting coalition. In Iowa in 2018, Hubbell won the group by 15 percentage points, an improvement of 4 points compared to 2016, and a 15 point gain since 2014 in which the group split 50/50. Turnout was also higher among this group than during the midterms of the Obama presidency; voters ages 18–29 were 11 percent of all votes cast in 2018, compared to just 9 percent in 2014.

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The shift in support among this middle partisan group over time is considerable, as visualized in the graph below:


Rural white voters, who make up 45 percent of the electorate, supported Hubbell at a rate 6 percentage points higher than Clinton. Contrary to many of the prevailing media narratives, Catalist finds no significant difference in partisan swing between rural and suburban voters in this state (Hubbell similarly performed 6 percentage points better than Clinton among suburban White voters). Swings in persuasion among urban Iowans probably did not have a significant impact on the outcome of the election simply because they made up only 3 percent of the electorate.


How did Hubbell perform better than Clinton among this Republican-leaning cohort of rural voters but worse than Clinton among Republicans overall? Almost all of the improvement came from middle partisan and Democratic-leaning rural voters, as shown below:


Finally, voters ages 65+ narrowly flipped from Obama in 2008 to Romney in 2012, and subsequently voted for Trump by a 25 point margin in 2016. There was a substantial 12 point swing back towards Democrats in 2018. As 32 percent of all votes cast, closing the gap among this historically-Republican supporting group is critical to future success across the state.

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Thanks to Michael Frias.