The 39th Senate District falls entirely within the boundaries of San Diego County. Toni Atkins (D) has been the incumbent since winning in 2016.
This district shows the following party registration for the three largest political groups (the source is http://www.l2political.com):
Multiple Republicans ran in the primary for a seat that is really not that competitive. Here are the 2016 primary results:
Toni Atkins (D)- 66.3%
J. Bribiesca (R)- 11.0%
Richard Fago (R)- 4.5%
John Renison (R)- 18.1%
241,190 ballots were cast in this race. The numbers in the primary race provided foreshadowing of a big victory for Democrats in the general election. In November, Atkins got 62.5% of the vote and Renison got 37.5%.
In 2020, Atkins gets a free pass, with no opponents filing to run for this seat. This is not surprising since the seat is not very competitive. However, looking at how virtually all congressional seats were contested, I was surprised at how many races went uncontested.