Top-two primary
All candidates run in one primary regardless of party and the two with the most votes advance, so two candidates of the same party can meet in November. The forecast then marks the seat as safe for that party.
California › U.S. House of Representatives · November 3, 2026 · Updated Oct 16, 2026
California's 45th District
Top twoTran is very likely to win: Tran wins in 49 of every 50 simulations.
Tran (D)
98%
chance of winning
Vo (R)
2%
- Average margin
- D+15.3
- 80% of outcomes
- D+6 to D+25
- Partisan lean
- D+6
- Polls
- No pollsmodel only
Tran is clearly favored to win: Tran wins in 9 of every 10 simulations.
Tran (D)
91%
chance of winning
Vo (R)
9%
- Average margin
- D+13.4
- 80% of outcomes
- D+1 to D+26
- Partisan lean
- D+6
- Polls
- No pollsmodel only
How this race is decided
Range of outcomes
Final margin across our simulations; the white dashes mark the middle 80%.
The candidates
DemocraticIncumbent
Derek Tran
Incumbent U.S. representative
- Experience
- Statewide office or Congress
- Raised
- $5M
- From individuals
- $3.6M
- Spent
- $2.1M
- Cash on hand
- $3.3M
Money: FEC, through Jun 30, 2026.
Republican
Chuong Vo
Former mayor of Cerritos
- Experience
- Local office
- Raised
- $844K
- From individuals
- $793K
- Spent
- $548.2K
- Cash on hand
- $295.8K
Money: FEC, through Sep 30, 2026.
What goes into the forecast
Every ingredient's estimate of the final margin.
- National environment
- D+9.5Election Day forecast; federal races run in it
- Swing reaching this office
- 78%Of a shift in the environment, from past House races since 2016
- Pacific adjustment
- −1.2How House races in the region have run against lean and environment lately
Each estimate is a margin before national and statewide uncertainty is simulated. Horizon blends polls, fundamentals and a little of the similar-places estimate, weighting each by how precise it is; Pulse uses polls and similar places only.
Fundamentals inputs
| Incumbency (+1 D, −1 R) | 1 |
| Fundraising edge (log ratio of individual money) | 1.2 |
| Elected-experience edge | 0.67 |
| First-term incumbent | 1 |
| Seat's last result vs. expectation | 0 |
| Incumbent's last result vs. expectation | 0 |
Polls
No public polls of this race. The forecast relies on fundamentals and on polling of similar places.
The district
Lean D+6: how much more Democratic or Republican than the nation it votes for president.
Presidential vote
Precinct results re-aggregated to the current district lines.
Who lives here
- Population
- 747,186
- People per km²
- 2,901
- Adults with a B.A.+
- 35%
- White, no degree
- 13%of adults
- White 20%
- Hispanic 35%
- Black 2%
- Asian 39%
- Other / multiracial 4%
American Community Survey 2020–2024, aggregated from census tracts.
Past results
Results in the same-numbered district; earlier elections may have used different lines.
2024 Earlier district lines
315,738 votes · D+0.2✓ Derek Tran (D)50.1%
Michelle Steel (R)49.9%
2024 President Vote in this district
292,412 two-party votes · D+4.1 · D+5.6 vs. the nation✓ Kamala Harris (D)52.0%
Donald Trump (R)48.0%
2022 Earlier district lines
217,426 votes · R+4.8✓ Michelle Steel (R)52.4%
Jay F Chen (D)47.6%
2020 Earlier district lines
414,939 votes · D+6.9✓ Katie Porter (D)53.5%
Greg Raths (R)46.5%
2020 President Vote in this district
330,989 two-party votes · D+10.3 · D+5.8 vs. the nation✓ Joe Biden (D)55.2%
Donald Trump (R)44.8%
2018 Earlier district lines
305,289 votes · D+4.1✓ Katie Porter (D)52.1%
Mimi Walters (R)47.9%
2016 Earlier district lines
311,849 votes · R+17.1✓ Mimi Walters (R)58.6%
Ron Varasteh (D)41.4%
2016 President Vote in this district
241,492 two-party votes · D+22.4 · D+20.2 vs. the nation✓ Hillary Clinton (D)61.2%
Donald Trump (R)38.8%