What Happened in the CA-25 Congressional Election? (2018)

Please note: The analysis below is based on an initial estimate of the 2018 electorate. Catalist released an updated analysis of the 2018 electorate in May 2019.


February 1, 2019

Author: Bennett Hillenbrand, Catalist Analytics

  1. How similar was Hill’s coalition to Clinton’s coalition since they carried the district by almost equal margins?
  2. Given that both Hill and Clinton carried a district Obama lost a few years prior, how were their coalitions different from his base of support?
  3. If national sentiment shifts back towards the Republicans in 2020, what are some strategies that might help Hill keep her seat?

And there were few differences when looking at the past partisan performance of precincts between 2016 and 2018 as well — that is, Hill didn’t really improve or lose ground compared to Clinton as a function of partisan behavior in the district. In the graph on the left we see almost identical performance between Clinton and Hill across precincts and in the graph on the right we see a very minor improvement for Hill among the 50/50 precincts, but Hill and Clinton performed essentially the same among highly Democratic or highly Republican areas of the district:


Given that, it makes sense to look at 2012 as well, where we see Hill showing an improvement over Obama performance, but it is a fairly uniform shift up. Looking at this another way on the right, however, we do see that Hill overperformed Obama by about 5 points in the precincts where Obama split the vote 50/50 with Romney in 2012, as well as a slightly better performance in the precincts Obama won:


And the real story is that this improvement among Historical Middle and Historical Republican voters came from the women within those groups:


Looking specifically at the dynamics among women voters, we see evidence of the improvement for both Hill and Clinton among middle aged Asian American and Latina women, as shown n the chart below, representing Hill (in red) and Clinton (in black), respectively, 10 to 15 points above the green line representing Obama’s level of support for these groups. Given the lower margins for Hill and Clinton among men of color compared to Obama and the higher margins among women of color, there seem to be gender dynamics at play within this district: