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U.S. House · All Illinois races

Illinois District 12

Solid R
Compare
Julie Fortier
Democratic
0 in 100
50–50chance of winning, out of 100
Mike Bost
Republican · incumbent
100 in 100

Mike Bost wins in 100 of 100 simulations.

There are no qualifying public polls yet, so the forecast leans on fundamentals; partisan lean, the national environment and incumbency point to Mike Bost +38.7.

Where the result could land

Every simulated outcome, grouped in 2-point steps. Projected margin Bost +38.7; 80 in 100 fall between Bost +46.0 and Bost +31.5.

Bost +30Bost +20Bost +10Fortier +10Fortier +20Fortier +30Tie

The candidates

Mike BostIncumbent
Republican
No biography on file yet.
Julie Fortier
Democratic
No biography on file yet.

Ballot list and short bios from Wikipedia (CC BY-SA); websites from Wikidata.

What if this race flips? Try it in the map builder →

Polls

No public polls have tested Julie Fortier against Mike Bost yet.

No polls of this matchup yet, so there is no polling average. The forecast relies on fundamentals.

Chance of winning over time

How this race’s odds have moved as polls and the national environment changed.

No change over the past 3 months
020406080100Aug 1Sep 1Oct 1

Out of 100. Today: Fortier 0, Bost 100.

What’s driving the forecast

The model blends each estimate by how much to trust it right now. Polls get 0% of the weight, 15 days out.

Polling average (after adjustments)—no polls
Partisan lean (Cook PVI, 2026 lines) R+22.0roughly 44 points of margin vs. the nation
National environment D+9.6generic ballot + presidential approval
Incumbent’s track record Bost +0.7In 2024 they ran 1.4 pts more Republican than the state’s lean predicted; half carries over (max 10)
IncumbencyBost +3.6incumbent’s side
Fundamentals estimateBost +38.7±6 typical error
Expert ratings (average)—used only in the “+ Expert ratings” version
ForecastBost +38.7±5.7 standard deviation, including 2.3 for movement before Election Day

All three versions

  • Polls only: Julie Fortier 0 in 100 (Solid R)
  • Polls + fundamentals: Julie Fortier 0 in 100 (Solid R)
  • Polls + fundamentals + experts: Julie Fortier 0 in 100 (Solid R)

Rules and notes

  • Incumbent renominated

House races, closest first · this is #302 of 421