The Daily Kos Elections team has been filling in a spreadsheet showing "presidential election results for both the 2016 and 2012 elections according to the congressional district lines used in the 2016 elections." A few points jumped out as I looked at the Iowa numbers, just added this week.
Let's start with the bad news.
Huge vote shifts delivered all four Congressional districts to Donald Trump.
Iowa's 15-point swing toward the Republican presidential candidate from 2012 to 2016 was
larger than that of any other state larger than in every state but North Dakota and West Virginia--one reason I'm so pessimistic about the next couple of election cycles here.
When a candidate won a state by nearly ten points and gained more votes in 93 of 99 counties, it's no shock that he carried each of the four Congressional districts. Still, Iowa Democrats are used to thinking of the eastern part of the state as friendly territory, so it's jarring to see that Hillary Clinton didn't win a plurality in any Congressional district.
IA-01 went for Barack Obama in 2012 by 56.2 percent to 42.5 percent but went to Trump this year by 48.7 percent to 45.2 percent.
IA-02 went for Obama in 2012 by 55.8 percent to 42.7 percent but went to Trump this year by 49.1 percent to 45.0 percent.
IA-03 went for Obama in 2012 by 51.4 percent to 47.2 percent but went to Trump this year by 48.5 percent to 45.0 percent.
IA-04 went for Mitt Romney in 2012 by 53.4 percent to 45.3 percent but went to Trump this year by 60.9 percent to 33.5 percent. Clinton carried only one of the 39 counties in the fourth district: Story (Ames). Obama had also managed to win Woodbury (Sioux City), Cerro Gordo (Mason City), Webster (Fort Dodge), Boone, Floyd, and Chickasaw counties in 2012.
More bad news, if you're a Democrat hoping to win back seats held by Representatives Rod Blum and David Young someday:
U.S. House incumbents outperformed their party's presidential nominee in every Iowa district.
Going into the 2016 election cycle, first-termer Blum was considered among the most vulnerable House members in the country, a fluke winner thanks to the GOP midterm wave. But he won re-election with 53.7 percent of the vote, running about 5 points ahead of Trump in IA-01.
Representative Dave Loebsack, the only Democrat left in Iowa's Congressional delegation, ran about even with Obama during the last presidential election year, winning 55.6 percent of the Congressional vote in IA-02. This year, he managed 53.7 percent of the vote, nearly nine points ahead of Clinton.
Young was another top target for House Democrats, but he won a second term with 53.4 percent of the vote, like Blum about 5 points ahead of his party's presidential nominee. Young said as little about Trump as possible all year and stayed away from the Republican National Convention as well as Trump's rallies in Iowa.
Representative Steve King only did a little better than Trump in IA-04, defeating his Democratic challenger with 61.2 percent of the vote.
Given these results and Iowans' tendency to re-elect their Congressional incumbents, national committees are less likely to pour a lot of resources into beating Blum or Young in 2018.
For Democrats who prefer to view the glass as half-full, I offer some less-bad news.
Trump exceeded 50 percent of the vote in only one Iowa Congressional district.
Trump won our state by a convincing margin, but he doesn't have much of a mandate in the Congressional districts where he received 48.7 percent, 49.1 percent, and 48.5 percent of the vote, respectively.
If Trump's approval rating tanks after using the presidency to enrich his family, or signing off on deeply unpopular policy like privatizing Medicare, Democratic challengers might hope for an opening against Blum and Young.
Finally, the most surprising news.
Iowa's first and second districts didn't vote more Democratic than the third district.
Before this election, the "partisan voting index" for each Iowa Congressional district was D+5 for IA-01, D+4 for IA-02, even for IA-03, and R+5 for IA-04. Developed by the Cook Political Report, "the Cook PVI measures how each district performs at the presidential level compared to the nation as a whole."
The more Democratic PVIs for the first and second Congressional districts reflect the fact that in 2008 and 2012, Obama did better in those areas than in the counties that make up IA-03.
I don't know what to make of IA-03 voters backing Clinton and Trump at about the same level as their counterparts in eastern Iowa this year. Does the result point to effective GOTV by the Democratic coordinated campaign in Polk County (where more than half of the Congressional district's voters live)? Or was some other factor connected to Clinton's greater collapse in IA-01 and IA-02, relative to Obama's performance in 2012 (such as those districts being less "urban" than IA-03)? I welcome feedback from Bleeding Heartland readers, either in a comment or guest post here, or via private communication.
When new PVIs are calculated based on the 2012 and 2016 presidential voting, the ratings for all of Iowa's districts will change. IA-01 and IA-02 will retain a slightly more Democratic PVI than IA-03, because Obama performed better in the eastern districts in 2012. But looking ahead to the next two cycles, I wouldn't assume voters in eastern Iowa will be more naturally receptive to Democratic candidates.
Any relevant comments are welcome in this thread.
P.S.- Iowa's statewide PVI was D+1 before the latest election, because our state's presidential voting in 2008 and 2012 had tracked closely to the national trendlines. Looking only at the 2016 presidential voting would give Iowa a PVI of R+6, on par with Texas.