Democratic
Missouri › Missouri House of Representatives · State legislature · November 3, 2026 · Updated Oct 16, 2026
Missouri House District 108
Costlow is very likely to win: Costlow wins in 49 of every 50 simulations.
Scott (D)
3%
chance of winning
Costlow (R)
97%
- Average margin
- R+14.5
- 80% of outcomes
- R+24 to R+5
- Partisan lean
- R+22
- Polls
- No pollsmodel only
Costlow is clearly favored to win: Costlow wins in 19 of every 20 simulations.
Scott (D)
6%
chance of winning
Costlow (R)
94%
- Average margin
- R+15.8
- 80% of outcomes
- R+28 to R+4
- Partisan lean
- R+22
- Polls
- No pollsmodel only
Range of outcomes
Final margin across our simulations; the white dashes mark the middle 80%.
The candidates
RepublicanIncumbent
Mike Costlow
What goes into the forecast
Every ingredient's estimate of the final margin.
- National environment
- D+9.5Election Day forecast
- Missouri state offices
- +0.6Polls for governor, statewide and legislative races · details
- Environment here
- D+10.1Used by the fundamentals
- Swing reaching this office
- 58%Of a shift in the environment, from past legislative races since 2016
- Midwest adjustment
- +0.3How legislative 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) | -0.76 |
| Elected-experience edge | -0.67 |
| First-term incumbent | 0 |
| Seat's last result vs. expectation | -2.63 |
| Incumbent's last result vs. expectation | -2.63 |
Polls
No public polls of this race. The forecast relies on fundamentals and on polling of similar places in the state.
The district
Lean R+22: 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
- 46,390
- People per km²
- 1,102
- Adults with a B.A.+
- 49%
- White, no degree
- 43%of adults
- White 84%
- Hispanic 4%
- Black 5%
- Asian 3%
- Other / multiracial 5%
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
20,804 votes · R+27.4✓ Mike Costlow (R)62.8%
Susan Shumway (D)35.7%
Patrick Andrew Miller (—)1.5%
2024 President Vote in this district
20,398 two-party votes · R+21.6 · R+20.1 vs. the nation✓ Donald Trump (R)60.8%
Kamala Harris (D)39.2%
2022
13,923 votes · R+27.8✓ Justin Hicks (R)63.9%
Susan Shumway (D)36.1%
2020 Earlier district lines
23,505 votes · R+29.4✓ Justin S Hill (R)64.7%
Susan Shumway (D)35.3%
2020 President Vote in this district
17,639 two-party votes · R+24.1 · R+28.7 vs. the nation✓ Donald Trump (R)62.1%
Joe Biden (D)37.9%
2016 President Vote in this district
15,065 two-party votes · R+33.7 · R+35.9 vs. the nation✓ Donald Trump (R)66.9%
Hillary Clinton (D)33.1%