On Tuesday, Missouri Democrat Mike Revis won a special election for the state’s 97th House District, barely flipping a district that Donald Trump won by 28 points. Democrats are happy about the victory, using it to argue that voters are generally unhappy with the Republican party. Republicans, meanwhile, are citing idiosyncratic state and local factors—like the allegations that Eric Greitens, the state’s Republican governor, blackmailed his mistress—to explain the loss.
This should all sound familiar. (OK, maybe the blackmail part shouldn’t.) This basic pattern—Democrats strongly outperforming Hillary Clinton’s margin in recent special elections—is nothing new.
This graphic is basically a timeline of House and state legislative special elections since Trump was inaugurated (constructed using data and sources from this Daily Kos Elections spreadsheet). Each point is a special election, and the graphic reads chronologically left to right (more recent elections are farther to the right). The vertical position shows how the special election result compared to 2016 (higher points indicate a greater Democratic over-performance, and lower points mean Republicans outperformed Trump). The size of each circle represents the total number of votes cast for the two major party candidates (bigger circles mean more people voted). And the color represents which party won (pink means Republicans held their seats and dark blue indicates Democrats took over a seat).
The message of the graphic (an updated version of the one I posted here) is simple. Democrats have, on average, been outperforming Hillary Clinton since Trump was inaugurated. There’s a lot of variance here (as the graphic shows, results have ranged from Republican overperformance to truly massive Democratic overperformance), but on average these Democrats have outperformed Clinton’s margin by about 12 points.
Revis’s 31-point over-performance is larger than average, and unlike many other Democratic overperformers, he actually flipped the seat. But a quick look at the graphic shows that some other Democratic candidates have performed about as well as Revis has (the small dark blue dot in the top right-hand corner) when compared to the 2016 baseline.
In other words, Revis’s win is consistent with a broader pattern of Democratic overperformance in special elections. These data don’t conclusively tell us whether Revis won by turning out Democrats or persuading Trump voters; other election wonks have made good cases for both, and the explanations aren’t mutually exclusive. But either way, strong Democratic special election performance is a bad sign for the GOP. Special elections, when compared to the appropriate baseline and aggregated, can foreshadow the eventual midterm results. And while Republicans have been gaining in generic ballot polls, these results are a reminder that the House majority is still far from safe.
