As you may have heard, a Blue Wave hit America on Tuesday night. Or was it a ripple or a splash? It definitely wasn’t a blue tsunami. But it wasn’t a red tide, either.
These phrases were all over headlines for the 2018 U.S. midterms. It’s hard to believe that less than twenty years ago they could have totally confused you. By now, the arbitrary color-coding of two political parties has become utterly axiomatic in American language and visual culture. There’s a reason those MAGA hats are crimson.

And guess what? A map did it. Our partisan palette—blue for Democrats, red for Republicans—originated in the election maps the media produced for the 2000 presidential race.
Previously, TV stations, newspapers, and political atlases mostly followed their own aesthetic whims when it came to coloring thematic election maps, which date back to the 19th century. Sometimes they threw yellow and green in the mix, which would now seem totally blasphemous, though red and blue, being the hues of the American flag, have always been popular picks. But their respective assignments have varied; blue just as often repped Republicans and red, Democrats, through the end of the 20th century. And, confusingly, in other countries, the fiery shade is usually associated with leftist parties. That wasn’t always the case in the U.S. ”It’s beginning to look like a suburban swimming pool,” one television anchor reportedly said in November 1980, as Ronald Reagan’s landslide victory over Jimmy Carter became manifest in a blue-tiled map.

But the turn of the millennium was another fraught time in American politics. It took weeks for the nation to learn whether George Bush or Al Gore had won the presidency, as poll workers recounted the ballots in Florida. Because electoral maps were on screen and in print so often, producers and publishers figured consistency would help viewers follow along. So they conformed to the same colors, and from that point on, they really, really stuck. That’s how you automatically knew the “red tide” wasn’t some kind of biblical meteorological event—although the elections did sometimes feel like that.
Does our two-sided color-wheel have any effect on our political affinities? A color psychologist told the New York Times in 2004 that it’s hard to say if people are more drawn to something by its associated color. But one 2016 study published by the National Institutes of Health suggests colors can drive parties apart. Psychology researchers tested how readers reacted to news articles about Russia and NATO when each subject was represented on a map as red and blue, respectively (their old Cold War-era designations), compared to how they perceived other color combinations.
The result: Participants who already had negative beliefs about Russia read the sides as being more antagonistic, but only when Russia was depicted in red. In other words, the colors reinforced political perceptions and stereotypes. Somehow, it’s not hard to imagine the same is true of the un-united red and blue states.
What do you think? Write me with your thoughts.
A cartographic feast
Elections are always a feast for map nerds, and these midterms were no exception. On CityLab, several recent stories have used maps to highlight what was at stake on Tuesday.
Up first, I wrote about a map by the amateur cartographer Philip Kearney that put a twist on voter turnout rates for the 2016 presidential election. Kearney showed how if no-show eligible voters had cast their ballots for “nobody”—the effective result of their abstention—“nobody” would have won the election rather than either of the actual candidates. And in a new series of interactive maps, Esri dug up more election data to show how non-voters helped elect Donald Trump.

Next, my colleague David Montgomery wrote about what the Republican landslide in the 2010 midterms portended for last night’s elections, when Democrats finally regained a majority in the U.S. House of Representatives. They had lost it eight years ago in an election that rewrote the country’s political geography around density. In 2010, Republicans started their domination of sparsely populated rural areas, Montgomery writes. The map he built to accompany the story shows how most GOP pickups in 2010 were in the country’s “pure rural” and “rural-suburban mix” districts. (Read about CityLab’s Congressional Density Index, which determines those classifications, here.)

Democrats had their turn at kicking off a new normal on Tuesday night, too, by taking control of the House with a “sweeping performance in suburban congressional districts,” Montgomery told me later. He writes for MapLab:
Democrats won 13 “sparse suburban” districts and another nine “dense suburban” districts, as categorized by CityLab’s Congressional Density Index. Democrats also won most of the remaining Republican-held urban districts, but made few gains into rural districts where they are a distinct minority.
And here’s his map that shows where it happened.

Mappy links: Midterms edition
Ending gerrymandering was a big theme among the progressive victories on Tuesday’s ballots—voters in Colorado, Michigan, Missouri, and Utah approved redistricting measures. Here’s CityLab’s Kriston Capps on why that matters, and the story of one Michigander who led a social media crusade to fix her state’s district lines. The New York Times had two great stories about election cartography this past week: one about their in-house practices, and another about the eye-popping, effects-laden maps that TV stations use.
Of all the excellent visualizations of Tuesday night’s returns, this package of maps and graphics from the Guardian stood out.
Mm, the Bloomberg Graphics team baked a House Cake.
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See you in two years—er, I mean, December! MapLab will be taking a Thanksgiving break. Have a happy holiday.
Laura