Special elections in 2017 were one of the first signs that Democrats were going to have a really good 2018. The party’s candidates were consistently outperforming the baseline partisanship of their districts in both federal and state-level special elections, something that tends to foreshadow the national political environment in the next congressional election. But the signal from special elections so far in 2019 is a lot weaker.
So far in the 2020 cycle, there haven’t been any special congressional elections like the high-profile 2017 races for the Georgia 6th District and a U.S. Senate seat in Alabama.1 But as of April 15, there have been dozens of special state-legislative elections across 15 states, including 27 elections that we think can be used to measure which party is performing better than we might expect based on partisanship alone. (This includes both traditional Republican-versus-Democrat races and all-party primaries but excludes nonpartisan elections and uncontested races. The exact criteria for determining which elections made the cut are in the footnote.2)
It’s not enough to look only at which party won these special elections — it’s also important to account for how red or blue a district normally is to understand whether a swing is happening. To do this, we compared the vote share margin in each special election with the district’s FiveThirtyEight partisan lean.3
The difference, or “margin swing,” tells us how much more Democratic or Republican the district was in the special election than it “should” have been in a neutral political environment. Historically, an average of these margin swings has proved predictive of the national mood in the next regularly scheduled federal election. But as you can see in the table below, special election results in 2019 have been all over the place, making it difficult to ascertain a clear pattern of overperformance for one party or the other.
|Date||Seat||Partisan Lean||Special Margin||Margin Swing|
|April 2||Pennsylvania SD-37||R+11||D+4||D+15|
|April 2||Maine HD-52||D+25||D+33||D+8|
|March 30||Louisiana HD-18||R+14||D+37||D+51|
|March 26||South Carolina SD-06||R+37||R+11||D+25|
|March 26||California SD-33*||D+58||D+57||R+1|
|March 26||California SD-01*||R+21||R+39||R+18|
|March 19||Minnesota HD-11B||R+23||R+37||R+14|
|March 19||Iowa SD-30||D+3||D+15||D+12|
|March 12||Texas HD-125||D+19||D+17||R+3|
|March 12||Tennessee SD-32||R+45||R+68||R+23|
|March 12||Pennsylvania HD-114||R+2||D+25||D+27|
|March 12||Maine HD-124||D+17||D+30||D+13|
|March 5||Kentucky SD-31||R+53||R+5||D+47|
|Feb. 26||Connecticut HD-99||R+5||R+8||R+3|
|Feb. 26||Connecticut SD-06||D+22||R+6||R+29|
|Feb. 26||Connecticut SD-05||D+25||D+29||D+4|
|Feb. 26||Connecticut SD-03||D+19||D+18||R+2|
|Feb. 23||Louisiana HD-27||R+68||R+84||R+16|
|Feb. 19||Virginia HD-86||D+26||D+25||R+1|
|Feb. 12||Georgia HD-176*||R+44||R+71||R+27|
|Feb. 5||Minnesota SD-11||R+7||R+6||D+0|
|Jan. 29||Texas HD-145*||D+27||D+49||D+22|
|Jan. 29||Texas HD-79*||D+32||D+60||D+28|
|Jan. 8||Virginia SD-33||D+23||D+40||D+17|
|Jan. 8||Georgia HD-05*||R+66||R+91||R+24|
|Dec. 18||Virginia HD-24||R+35||R+19||D+16|
|Dec. 11||Texas SD-06*||D+36||D+54||D+18|
Democrats have had some massive overperformances, such as in South Carolina Senate District 6, where their candidate lost by only 11 points in an R+37 district. But Republicans have had some big-time successes as well, like when they won Connecticut Senate District 6, a D+22 seat, by 6 percentage points. Still other results barely deviated from the district’s partisan lean.4
Out of the 27 special elections in the table above, Democrats outperformed partisan lean in 15 of them, while Republicans outperformed it in 12. Compare that with the much more lopsided ratio in special-election performance through this point in the 2018 election cycle (April 15, 2017): Democrats had overperformed in nine out of 11 races.5 Similarly, the average margin swing at this point last cycle was much more Democratic-leaning than it is this cycle. So far, this cycle’s special elections have had an average 5-point margin swing toward Democrats relative to partisan lean, but at this point in 2017, Democrats were overperforming by 11 points on average.
This might suggest that 2020 will be a slightly Democratic-leaning year — just maybe not on the same level as 2018. Then again, with 2019’s margin swings so spread out (from +29 for Republicans to +51 for Democrats), I’m not sure it tells us much yet.
Other early indicators of the national political environment are similarly inconclusive. Democrats lead most early polls of the generic congressional ballot by single digits, but almost all of those polls have been conducted by one pollster, HarrisX, which FiveThirtyEight gave a C+ pollster rating in 2018. So if their numbers are off, our whole picture might be biased. In 2018, Republican retirements from Congress — and robust candidate recruiting by Democrats — were also early signs of Democratic strength, but it’s too early to draw any conclusions from those factors for the 2020 cycle. Only two Republicans and two Democrats have announced that they are retiring from Congress and not running for higher office, and both parties have landed solid recruits in other races that are expected to be closely fought.
Taking everything into account, 2020 looks a little better for Democrats than for Republicans right now, but we probably shouldn’t read too much into so little data. We’ll just have to wait until we’re further along in the cycle.