While the GOP was able to gerrymander their districts to lock in majorities in states like Georgia, North Carolina, and Wisconsin, it's a different story in Iowa. In the Hawkeye State, both legislative and congressional maps are drawn by an independent commission and sent to the legislature for approval. If the legislature rejects three of the commission's maps, it's then given the chance to draw its own districts, but the Democratic Senate and GOP House approved the commission's initial proposals without any fuss in 2011.
You would expect (or at least hope) that a process like this would lead to less distorted outcomes than when lawmakers draft their own maps for pure partisan gain, and indeed, that appears to be the case. One way to visualize how much these lines do, or don't, favor one party is to sort each seat in each chamber by Clinton's margin of victory over Trump and see how the seat in the middle-known as the median seat-voted. Because both chambers have an even number of seats, we average the two middle seats to come up with the median point in the chamber.
In the state Senate, the median seat backed Trump 54-40, a bit to the right of his 52-42 statewide win, but not dramatically so. Meanwhile, in the state House, the median seat backed Trump 53-41, not too different from his statewide margin of victory. Similarly, four years earlier, when Obama won Iowa 52-46, he carried 2012's median Senate seat 53-46 and the median House seat 51-47-again, similar to his statewide margin.
But just because these maps aren't partisan gerrymanders doesn't mean they're good news for Democrats: If the 2018 electorate still supports Trump, Team Blue is going to have a very challenging time winning control of either chamber. At the same time, Obama's performance shows that a swing to the left would put plenty of seats in play.
As we mentioned above, only half of the state Senate goes before voters next year: Even-numbered seats are up in presidential cycles, while odd-numbered seats are up in midterm years. Unfortunately for Team Blue, the huge losses they took last year will make it extremely tough to cobble together a Senate majority in just one cycle. Trump's landslide helped Republicans win 19 of the 25 Senate seats that were up for election, so if Democrats want to take a narrow majority next year, they'll need to win 20 of the 25 seats that will be on the ballot. Democrats hold 13 of those seats, while David Johnson, the aforementioned Republican-turned-independent, is also up.
Of those 13 Democrats, five represent Trump seats, all of which backed Obama in 2012. The Trumpiest seat in the bunch is held by Democratic state Sen. Tod Bowman, whose Dubuque-area SD-29 swung from 52-47 Obama to 58-37 Trump. Johnson's old party will also have a chance to take revenge on him next cycle. His SD-01, located in the state's northwest corner, went from 63-36 Romney all the way to 71-25 Trump. Johnson recently said he hasn't decided if he'll seek re-election.
Of the 11 Senate Republicans up next year, only one represents a seat that Clinton carried, though Roby Smith's Davenport-area SD-47 still saw a small swing to the right, going from 51-48 Obama to 47.1-46.5 Clinton. And only one more Republican who's up in 2018 even represents a seat that Obama had carried: Southeastern Iowa's SD-41, represented by Mark Chelgren, went from 53-45 Obama to 57-38 Trump. Chelgren made national news earlier this year after NBC reported that the business degreeChelgren claimed to have was actually a training certificate from his time working at Sizzler when he was 19. (Admittedly, this is still more impressive than a degree from Trump University.)
It will be tough enough for Democrats to protect all 13 of their seats and capture those two Obama seats, and it would be even more work to take the additional five districts they'd need for a majority without Johnson's help. Even if you look at just the Romney numbers, the math is horrible. Of the seven Republicans up next year in Romney districts, Romney's fifth-best seat, SD-09, backed him 57-42. As for the Trump numbers, SD-09 supported The Donald 69-27. Democrats may be able to make gains next year, but retaking the Senate will almost certainly require two solid cycles in a row.
It's not all bad news, though, since, as we noted above, the entire 100-person House is up every two years. The GOP currently holds a 59-41 majority, with Daily Kos Elections assigning any vacant seats to the party that last held them. (GOP state Rep. Greg Forristall recently died; at 62-37 Romney and 66-30 Trump, his HD-22 probably isn't going anywhere in a special election.)
Ten Democrats hold Trump seats, while four Republicans represent Clinton turf. The reddest Democratic-held district is HD-82 in southeast Iowa, which swung from a small 50-48 Obama win to 58-37 Trump; however, Democratic state Rep. Curt Hanson faced no opposition last year despite his tight 2014 re-election. Not far behind is Todd Prichard, who recently announced that he would run for governor. Prichard's HD-52 went from 56-43 Obama to 57-38 Trump, the fourth-largest swing towards Trump in the chamber; Prichard still won re-election 54-46. The other eight Trump-district Democrats also represent seats that had backed Obama in 2012.
The bluest GOP-held seat is HD-43 in the Des Moines-area, which went from 51-48 Obama to 53-41 Clinton, making it one of the very few seats in either chamber that swung towards Clinton. How few? Clinton's margin of victory was stronger than Obama's in only 15 state House seats and five Senate seats. Despite the swing, Republican state Rep. Chris Hagenow won re-election 52-48 last cycle in HD-43.
But if 2018 looks a whole lot more like 2012 than 2016, Democrats will have plenty of targets. Just one Democrat, HD-40's John Forbes, represents a Romney seat. This Des Moines-area district was one of just two state House seats and two Senate seats to go from Romney to Clinton, swinging from a narrow 49.5-49.3 Romney to 50-43 Clinton; Forbes won re-election 57-43. By contrast, 21 Republicans hold Obama seats, 17 of which backed Trump. Of course, even if Iowa swings left, Democrats aren't assured of anything. In 2012, even as Obama was carrying 61 House seats, Republicans still won a 53-47 majority, with 18 Republicans taking Obama districts to just four Democrats prevailing Romney turf.
Finally, one small bit of housekeeping. In early February, we learned that Dallas County had failed to report 5,842 votes in its tallies, a whopping 13 percent of the county's total. We recently acquired Dallas' updated precinct-by-precinct report, which you can find here. We've also updated our calculations for Iowa's 3rd Congressional District, which is home to Dallas County, but Trump's margin of victory barely moved at all there.