These numbers are extra essential than ever for understanding U.S. elections. Because of elevated political polarization and the decline of split-ticket voting, there’s now a really robust correlation between how a given district votes in presidential races and the way it votes for the Home. We are able to see this most vividly within the long-term decline of so-called “crossover” districts, which assist one social gathering’s candidate for president however the different’s for Home.
Following redistricting, simply 14 Democratic-held seats would have voted for Donald Trump whereas solely 15 Republican-held seats would have backed Joe Biden, as proven in the chart below:
That complete of 29 is the third-lowest in a century. The bottom determine in that timeframe got here simply previous to redistricting, when there have been 16 crossover seats. The rise is to be anticipated, since each events sought to redraw maps in methods favorable to them (albeit with Republicans doing so in additional states and extra aggressively), however the totals are prone to shrink once more following the midterms.
Armed with these district-level presidential outcomes, then, we are able to establish which races are prone to be aggressive, and we are able to predict the end result of most Home elections with a powerful diploma of confidence. In an period when the reliability of polling has appeared unsure, this tough knowledge provides an essential various. In fact, it isn’t the be-all, end-all, which is exactly why Every day Kos Elections tracks marketing campaign information so carefully and shares it every day in our Morning Digest newsletter, but it surely’s a essential part of all good Home election evaluation.
There are various different issues this new knowledge tells us, too. On the highest degree, we all know that Biden would have carried 226 districts whereas Trump would have prevailed in 209, a slight improve from Biden’s 224-211 edge previous to redistricting. However that topline obscures the best way during which Republican gerrymandering has elevated the GOP’s benefit on what was already a enjoying subject tilted in its favor.
We all know this as a result of the one most essential reality this knowledge reveals is the id and traits of what is generally known as the “median district.” A useful technique to assess how a lot the nationwide congressional map favors one social gathering or the opposite is to type every seat by Biden’s margin over Trump (or vice versa) and see how the seat within the center—the median seat—voted.
That district is now Michigan’s eighth, a Democratic-held seat based mostly across the metropolis of Flint that will have voted for Biden by a 50-48 margin. On the floor, which may seem to be welcome information for Democrats: In the event that they have been to seize each seat bluer than the eighth—a helpful framework for illustrative functions—they’d win a majority within the Home.
However this district is in truth to the proper of the nation as a complete. Biden gained the nationwide well-liked vote by a margin of slightly below 4.5 factors, so his efficiency in Michigan’s eighth (the place his margin of victory was a shade over 2 factors) is 2.4 factors worse. With the Home so carefully divided, these 2.4 factors might make all of the distinction. What’s extra, this new median is additional to the correct than the pre-redistricting median, Illinois’ outdated 14th District, which was 2 factors worse than Biden’s nationwide vote.
In fact, even in a wave election, Democrats virtually actually would not win each district bluer than Michigan’s eighth—there’ll all the time be some crossover seats (the lowest since 1900 was five, in 1904). However trying on the numbers this manner illuminates the built-in benefit that Republicans have earlier than even a single vote is forged, and the way that benefit grew this 12 months because of gerrymandering.
There’s rather more, particularly on the degree of particular person districts. As an illustration, the bluest seat that Republicans are defending is Texas’ thirty fourth within the japanese Rio Grande Valley, which might have voted for Biden by a 57-42 margin. There’s an asterisk right here, although, since two incumbents are working in opposition to each other: Republican Rep. Mayra Flores, who flipped the outdated thirty fourth in a particular election earlier this 12 months, and Democratic Rep. Vicente Gonzalez, who opted to depart behind his outdated fifteenth District subsequent door and run within the bluer thirty fourth.
When you’re in search of a extra simple reply, you will discover it in California’s twenty second within the southern Central Valley, which might have backed Biden 55-42. Rep. David Valadao is consequently one of the vital susceptible Republicans this 12 months and faces a stiff problem from Democratic Assemblyman Rudy Salas. Valadao is used to the headwinds, although, as his outdated district supported Biden by an identical 54-44 unfold.
His Democratic counterpart could be Rep. Tom O’Halleran, who noticed his sprawling 2nd District in northeastern Arizona change into significantly redder, going from 50-48 for Biden to 53-45 for Trump. That dramatic shift happened as a result of the unbiased tiebreaker on Arizona’s redistricting fee voted for a GOP plan that, nicely, favored the GOP.
Another notable superlatives that emerge from the information:
Closest seat within the nation: Arizona’s sixth, 49.3-49.2 Biden—a margin of 0.1%, or about 300 votes
Reddest seat within the nation: Alabama’s 4th, 80-19 Trump
Bluest seat within the nation: Maryland’s 4th, 90-9 Biden (Biden gained a barely increased vote share however a barely smaller margin in Pennsylvania’s third, which was additionally 90-9)
Reddest Democratic-held open seat: Georgia’s sixth, 57-42 Trump
Bluest Republican-held open seat: Illinois’ thirteenth, 54-43 Biden
District that received essentially the most redder: Tennessee’s fifth, 55-43 Trump (vs. 60-37 Biden)—a shift of 35 factors
District that received essentially the most bluer: California’s eighth, 76-22 Biden (vs. 55-43 Biden for its predecessor, numbered the third)—a shift of 42 factors
When you dive in your self, you will discover a lot extra. As soon as once more, you will discover all of our knowledge proper right here, and we strongly encourage you to bookmark the hyperlink. And if you would like to play with the numbers your self, we’ve also made a spreadsheet version available. Please tell us what you uncover!