On Dec. 19, the Census Bureau released its 2018 population estimates for every state, detailing how many residents each state has gained or lost since the 2010 census. The firm Election Data Services has used these estimates to project how many congressional seats each state might gain or lose in the 2020 round of reapportionment, which assigns each state its share of the House’s 435 districts based on its population.
As shown in the map above (see here for a larger version), 15 to 17 states could see their number of districts change after the 2020 census. The precise numbers vary because EDS offers two different projections: one based on longer-term population trends from 2010 through 2018, and a second based on the much shorter-term trend from just 2016 to 2018. A third projection, relying on trends from 2014 to 2018, yields the same results as the 2010 to 2018 timeframe. (A fourth model that looks only at the 2018 numbers is more of a snapshot rather than a forecast, so we haven’t included it in the map above.)
These projections also represent a shift, in some cases, from forecasts that EDS issued last year, when the Census Bureau released new population estimates for 2017. These five changes are summarized below:
|0 or -1
|0 or -1
|0 or +1
|+2 or +3
If California does indeed lose a seat, it would be the first time in 160 years that the Golden State’s representation in the House would shrink.
This scenario would only take place under the short-term model (based on population shifts from 2016 to 2018), in which case Minnesota would hang on to a seat it’s otherwise set to lose.
The 2020 census and subsequent reapportionment will thus set the stage for congressional redistricting. However, it’s difficult to predict with much accuracy what the partisan impact of these changes will be because we don’t yet know which party (if any) will control the redistricting process in many states.
The 2018 gubernatorial elections were an important piece for determining the partisan control over the process after 2020, but legislative races yet to take place in 2019 and 2020 will also be crucial for setting the partisan landscape. One thing we do know, however, is that much of the population growth in Sun Belt states like Texas comes from black, Latino, and Asian-American residents, which could benefit Democrats in those states. However, there could be a significant undercounting of those populations if the Trump administration's pernicious push to add an intimidating citizenship question to the census survives ongoing court challenges.
Reapportionment will also determine how many Electoral College votes each state receives, since each state gets electoral votes equivalent to the number of House seats it has plus two for its Senate delegation. Adjusting the 2016 Electoral College outcome based on the above projections, Donald Trump would have gained three electoral votes, while Hillary Clinton would have lost three—not nearly enough to alter Trump’s 304-227 win.
Interestingly, the largely Midwestern and Northeastern states that are projected to lose seats almost all trended Republican in 2016, while the states forecast to gain seats—largely in the Sun Belt— almost all trended Democratic. These trends could benefit Democrats in the long term if they can start winning regularly in places like Arizona, Florida, North Carolina, and Texas, even if Republicans shift toward a greater reliance on the Rust Belt.