FutureBallotU.S. election forecasts, with every number traced to its source

IN-8 · House

election-day forecast · ground-up model · as of 2026-10-02

Safe R
0%
Mary Allen
Democrat
100%
Mark Messmer
Republican
Expected margin and its 90% range
R+40R+20R+10EvenD+10D+20D+40R+29.1
What moves this district (points of margin; blue toward the Democrat, red toward the Republican)
2024 presidential lean−16.1
2024 House lean−6.7
asian share−1.1
experience gap−0.6
median home value−0.5

The district, in brief

Indiana's 8th, on the map first used in 2022, is located in southwest and west central Indiana; it is anchored in Evansville and also includes Jasper, Princeton, Terre Haute, Vincennes and Washington.

The incumbent is Republican Mark Messmer, elected with 68.0% of the vote in 2024, who was unopposed in his primary. The Democratic nominee is Mary Allen, an at-large Evansville city councilor since 2023, who won her primary with 66.7% over Tabitha Zeigler, Christopher Rector and Mario Foradori. As of June 30, 2026 Messmer had raised $1,171,366 with $713,500 on hand; Allen had raised $294,502 with $179,307 on hand.

Every rater that gives a call lists the seat as R: Decision Desk HQ (July 14, 2026), the Cook Political Report (February 6, 2025), Inside Elections (March 7, 2025) and Sabato's Crystal Ball (July 15, 2025). Silver Bulletin is listed with a date of August 20, 2026 but no ranking is shown. The text records no district polls and no presidential results.

A paragraph quoting a model forecast from the day this brief was written is omitted; the current forecast is at the top of this page.

The facts, each beside its sentence

Incumbent
Mark Messmer (R)The incumbent is Republican Mark Messmer, who was elected with 68.0% of the vote in 2024.
Open seat
noThe incumbent is Republican Mark Messmer
Democratic nominee
Mary AllenMary Allen, at-large Evansville city councilor (2023–present)
Republican nominee
Mark MessmerMark Messmer, incumbent U.S. representative
Democrat's background
at-large Evansville city councilor (2023–present)Mary Allen, at-large Evansville city councilor (2023–present)
Republican's background
incumbent U.S. representativeMark Messmer, incumbent U.S. representative
Last result
Messmer elected with 68.0% in 2024who was elected with 68.0% of the vote in 2024
Primaries
Messmer was unopposed in the Republican primary (52,249 votes); Allen won the Democratic primary with 66.7% over Tabitha Zeigler (15.3%), Christopher Rector (11.8%) and Mario Foradori (6.2%)candidate: Mary Allen votes: 18,816 percentage: 66.7
Raters
Decision Desk HQ: R (July 14, 2026); Cook: R (February 6, 2025); Inside Elections: R (March 7, 2025); Sabato's Crystal Ball: R (July 15, 2025); Silver Bulletin listed (August 20, 2026) with no ranking shownDecision Desk HQ R July 14, 2026 The Cook Political Report R February 6, 2025
Money
As of June 30, 2026: Messmer raised $1,171,366, spent $664,971, $713,500 on hand; Allen raised $294,502, spent $115,194, $179,307 on handMark Messmer (R) $1,171,366 $664,971 $713,500
Also
District is anchored in Evansville and includes Jasper, Princeton, Terre Haute, Vincennes and Washingtonthe district is anchored in Evansville and also includes Jasper, Princeton, Terre Haute, Vincennes and Washington

Not in the source: No presidential results for the district appear in the text, and the facts have no presidential baseline.; No district polls in the text; the model's basis says no district polls.; Silver Bulletin appears in the predictions table without a ranking. Endorsement sections are empty.; No third-party or independent candidates are listed.

Read from the district's section of Wikipedia's state page (CC BY-SA), archived as 0c1a4f4bee4e; written by claude-fable-5-1 (batch reader) on 2026-09-30 and checked mechanically: every quote occurs verbatim in the archived text, every number in the brief occurs in the inputs. No probability here is the reader's.

Who holds the seat now

Mark B. Messmer (Republican), in this chamber since 2025, 1 term. Committees: House Committee on Agriculture; House Committee on Armed Services; House Committee on Education and Workforce.

From the congress-legislators dataset (CC0), archived as ae8cb9477c48. For a Senate race this lists both of the state's senators; the one whose term ends in the election year holds the seat on the ballot. For a House district redrawn for 2026 it is the member elected under the old lines with this number, who may be running elsewhere; the dossier above names who is running here.

How it has voted for president

Two-party margin201620202024
PresidentR+36.0R+33.4R+36.5

A shift of 0.5 points toward the Republicans from 2016 to 2024. county returns placed on the current lines by 2020 block population; MEDSL county file (2016), an MIT-licensed county file (2020, checked against certified state results) and MEDSL precinct returns (2024). For a district split across counties this is an estimate, and where the state published the exact 2024 figure for these lines, that exact figure is the one the model uses.

Who are the voters?

Group (adults 25+)Share of adultsTurnout 2020 / midtermShare of a midterm electorateEst. Democratic share, 2020
White, no degree71%56% / 39%65%19%
White, degree21%76% / 60%29%58%
Black4%59% / 31%3%91%
Hispanic2%27% / 12%1%59%
Asian1%38% / 21%0%64%
Other / multiracial2%59% / 40%2%57%

Of about 515,755 adults 25 and over. In 2020 the district voted 33.3% Democratic (two-party) for president. With the same preferences and a 2022-style midterm turnout, it would vote 33.5% Democratic: the midterm electorate alone moves the margin 0.4 points toward Democrats. Group shares are estimated from how results vary across the state's census tracts (ecological inference, anchored to Pew's 2020 validated-voter figures) and calibrated to this district's actual 2020 vote; turnout is the Census survey's state rate by race and national rate by education, whose state samples carry margins of several points.

Not answered here: how each group will vote in 2026. These are 2020 preferences; this profile is description, not yet an input to the forecast.

The money

CandidateRaisedCash on handPAC shareSelf-fundedOutside $ forOutside $ against
Messmer, Mark Mr. (REP)
incumbent
$1,171,366$713,50036%0%$0$0
Allen, Mary Theresa (DEM)
challenger
$294,502$179,3082%1%$0$0

FEC bulk candidate summaries through June 30, 2026; no independent expenditures reported for or against any candidate, which usually means nobody outside the district thinks it is in play.

The district in numbers

MeasureDistrictNationDifference
Bachelor's degree or higher, 25+22.6%34.9%-12.4 pts
White, non-Hispanic88.2%58.2%+30.0 pts
Black, non-Hispanic4.0%12.0%-8.0 pts
Hispanic or Latino3.2%19.0%-15.8 pts
Asian, non-Hispanic1.0%5.8%-4.8 pts
Foreign-born2.5%13.9%-11.4 pts
Median age40.039.20.8
Median household income$63,906$84,362$-20,456
Median home value$164,500$379,737$-215,237
Owner-occupied homes72.0%65.1%+6.9 pts
Unemployment, July 2026 (BLS county data)3.4%4.4%-0.9 pts
Change in unemployment, past 12 months-0.5 pts——
Change since the last election (24 months)-0.9 pts——
Unemployment (ACS)4.0%5.2%-1.2 pts
Federal government workers2.0%2.6%-0.6 pts
Work from home5.8%13.5%-7.6 pts
Households on SNAP9.5%11.8%-2.2 pts
Households with Social Security income35.0%31.2%+3.8 pts
Households with public assistance income2.1%2.7%-0.6 pts
Moved in from another state, past year1.9%2.3%-0.4 pts
Gini index0.500.440.06
Per-capita personal income (BEA), 2024$59,288$73,248$-13,960
Per-capita income growth since 2019, nominal, 202432.2%32.0%+0.2 pts
Government and other transfers, share of income, 202425.8%19.6%+6.2 pts
Social Security, share of income, 20228.1%5.8%+2.2 pts
Medicare, share of income, 20225.9%4.5%+1.4 pts
Medicaid, share of income, 20226.3%4.0%+2.3 pts
SNAP, share of income, 20220.4%0.6%-0.2 pts
Earned Income Tax Credit, share of income, 20220.4%0.4%+0.0 pts
Veterans' benefits, share of income, 20220.9%0.9%+0.0 pts
Federal civilian jobs, share of all jobs, 20221.9%1.3%+0.6 pts
Military jobs, share of all jobs, 20220.5%0.9%-0.4 pts

ACS 5-year 2023, the Census Bureau's own tabulation of this district (118th Congress lines). Unemployment is the BLS county series placed on the district by block population, not seasonally adjusted, so changes are same-month comparisons. Income, transfers and jobs are BEA county accounts placed the same way, compared with the average district. Every other figure is a named column of a named table in the Bureau's summary file, archived before it was read. This is what a reader knows about a district before looking at a poll; the model does not yet use it, and whether it should is a registered question.

Who is favoured, and by how much?

>99%
Mark Messmer
run 0b33151b · house_district_prior/0.2.0 · as of 2026-10-02
-29.1
expected margin, D-R
run 0b33151b · house_district_prior/0.2.0 · as of 2026-10-02

The 90% interval runs from -43.1 to -15.1 points, D-R. It is wide because this district has never been polled.

What is this built on?

A model trained on every contested House race 2012-2024 predicts this district's lean from its own record: presidential and House results on the current lines, incumbency, both candidates' prior offices, outside and party money before 1 October, demographics and public-assistance shares from the Census release before the election, local unemployment and income, and religious tradition. The national margin comes from presidential approval, the economy, the midterm penalty and the generic ballot corrected for its measured lean. Draws share national and state errors, so the seat total and this district come from the same simulation.

Not answered here: district polls, which are not yet folded in.

Why does the model say this?

Each figure is how far this district's predicted lean moves when that one feature is set to the typical value across 2026 districts, everything else held: 2024 presidential lean (R+35.2): 16.1 pts toward the Republican; 2024 House lean (R+36.8): 6.7 pts toward the Republican; asian share (1.0%): 1.1 pts toward the Republican; experience gap (-3 levels, D minus R): 0.6 pts toward the Republican; median home value (176337): 0.5 pts toward the Republican.

How sure is it, and of what?

Total sd 8.48 points, made of the seat's own volatility 90%, correlated polling error 10%. The decomposition is stored with the forecast rather than reconstructed, so a probability whose dominant input is a placeholder is visibly that.

Not answered here: a nowcast. 'If ballots were cast today' needs something that observes today, and for a House district nothing does. Publishing the election-day figure under both labels would make one forecast look like two.

How was this number made?

Run 0b33151b-a949-47f1-b845-564833a2b74d, house_district_prior/0.2.0, as of 2026-10-02. Promoted by a pre-registered gate: on 2016-2022 its Brier score was 0.036 against 0.049 for the previous method, and on a single 2024 run 0.023 against 0.032 (experiments/district_gate_result.md, with an independent review).