Riding profile

CA-4

US House district — CA · Mixed · us ca

The question

CA-4: a safe seat for the Democrats?

Editorial read

CA-4, a mixed riding in CA, elected a member with the Republicans in the previous cycle, with a 29-point margin. The Vote-Scope model projects the Democrats ahead at 61% vote share, against 39% for the Republicans, and the probability of a close race is negligible.

Sitting member

THOMPSON, MIKE MR.

Sits with Democrat

Who's running

The candidates

Declared and on-ballot candidates for the upcoming election.

  • Democrat Incumbent

    Thompson, Mike Mr.

  • Democrat Challenger

    Jones, Eric

  • Democrat Challenger

    Merrell, Trevor

  • Republican Challenger

    Brown, Sharon

  • Republican Challenger

    Ghusar, Mandy

  • Republican Challenger

    Mackenzie, Laurie John

  • Republican Challenger

    Riehle, Raymond

Current forecast

Democrat

Safe

Probability
100%
Mean margin (pts)
21.1
P(close race)
0%

Projected vote share

Projection by party

  • Democrat 60.5%
  • Republican 39.5%

In context

How this riding stacks up

Democrat Republican
HereCA-4 60.5%39.5%
National averageUnited States 51.9% +8.7 46.6% −7.2

Nationwide averages computed across the 435 riding-level projections (unweighted mean).

Projection track

How the projection has moved

Previous election · US HOUSE_2024

Won by
Republican
Margin
29.3 pts
Margin shift vs current projection
-8.2 pts

Redistricting impact

Where these voters came from

This district was redrawn under the 2025-2026 mid-decade redistricting. Composition by inherited old-district share:

  • Congressional District 4 (06004) 45%
  • Congressional District 1 (06001) 40%
  • Congressional District 3 (06003) 13%

Around the region

Nearby ridings

Tone only — pick a riding to see the numbers.

Last model run
Cycle
us_house_2026