nijinnUS Midterms 2026
Updated Oct 16, 2026, 1:45 PM ET
House · 3 November 2026

IL-12 House 2026

97.0% RMike Bost leads TruthIndex™Safe R
Polymarket
96.6%
Kalshi
97.4%
Spread
0.8 pts
24h
–
7 days
+1.0
Updated
Oct 16, 2026, 1:45 PM ET
Latest coverage

Live News

Recent coverage for IL-12 House.

  1. Endorsements: Glowiak Hilton for Senate Dist. 23; Deuter for House Dist. 45; Blair-Sherlock for House Dist. 46

    The article is a set of endorsements from the Daily Herald for Illinois races, including endorsements for Glowiak Hilton for Senate District 23, Deuter for Illinois House District 45, and Blair-Sherlock for Illinois…

    Daily HeraldFortier
  2. Former U.S. Rep. Melissa Bean seeks return to Congress in race vs. Republican Jennifer Davis - CBS Chicago

    The CBS Chicago article covers former U.S. Rep. Melissa Bean seeking to return to Congress in Illinois’ 8th District, challenging Republican Jennifer Davis.

    CBS NewsDavisEstiFortierHouchinMaxwellRegnitz
  3. Who is running for the U.S. House in the Chicago area during the 2026 midterm elections? - CBS Chicago

    The page appears to discuss who is running for the U.S. House in the Chicago area for the 2026 midterms, including information on candidates and elections in various districts.

    CBS NewsCastilloUnderwoodFordEstiFortierJacksonEllesonDavisMarterDecioFordCoxMillerHannonRamirezLaHoodBissMaxwellGegenMeyerRegnitzChai
  4. US Department Of Transportation Awards Grant To Effingham & Marion Counties To Expand Truck Parking

    U.S. Representative Mike Bost (IL-12) announced that a U.S. Department of Transportation grant will be used to expand and improve truck parking along Interstate 57 in Effingham and Marion counties, Illinois.

    effinghamradio.comFortier

Mike Bost, last 60 days

How to read this chart

The green line is the TruthIndex™, the chance of this outcome. It combines the prices on both venues and gives more weight to the venue with more money in its order book. The two thinner lines are Polymarket's and Kalshi's own prices, and the grey band between them shows how far apart the two venues are.

The pale bands behind the lines are the rating zones (Toss-up, Lean, Likely and Safe), so you can see when the race moved from one rating to another. Move along the chart, or use the arrow keys, to read the values for each day.

More in Methodology
TruthIndex™PolymarketKalshiGap between the venuesRating zones

All outcomes

OutcomeTruthIndex™PolymarketKalshiSpread24h
RMike Bost 97.0% 96.6% 97.4% 0.8 pts –
DJulie Fortier 2.2% 2.3% 2.0% 0.2 pts –
PolymarketKalshi

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Candidates & Background

Julie Fortier

Democratic

Julie Fortier, a Democrat who works as a research microbiologist and is an Air Force veteran, is the Democratic nominee for Illinois's 12th congressional district in 2026, facing Republican incumbent Mike Bost.

Mike Bost

Mike Bost

Republican U.S. Representative for Illinois's 12th congressional district (since 2015)

Mike Bost, a Republican who has represented Illinois's 12th congressional district since 2015 and chairs the House Committee on Veterans' Affairs, seeks re-election in 2026 against Democrat Julie Fortier.

Born 1960 · Murphysboro, Illinois

Margin of victory

Each venue's margin market, shown on its own: the two venues set their ranges differently.

Kalshi2.1K contracts

Illinois's 12th District margin of victory

Bost, 23+ pts
96.3%
Bost, 26+ pts
–
Bost, 29+ pts
73.5%
Bost, 32+ pts
67.0%
implied
Bost, 35+ pts
58.0%
implied
Bost, 38+ pts
47.0%
Bost, 41+ pts
32.0%
Bost, 44+ pts
19.0%
Bost, 47+ pts
8.7%
Bost, 50+ pts
7.7%
implied
Source: Kalshi market

Polymarket$24.3K traded

IL-12 House Election Margin of Victory

Democrat Wins
4.4%
Republican 0-10%
2.5%
Republican 10-20%
4.1%
Republican 20-25%
2.5%
Republican 25-30%
20.0%
Republican 30-35%
25.5%
Republican 35-40%
28.0%
Republican 40-45%
13.1%
Republican 45-50%
10.8%
Republican 50%+
1.0%
Source: Polymarket market

Each venue's market

Polymarket$25.3K traded

Prices which party wins.

Mike Bost: Counted · bid 94.4% / ask 98.9% · $2.0K within 5 pts

This market will resolve according to the party of the candidate who wins the IL-12 congressional district seat in the U.S. House of Representatives in the 2026 midterm elections. The midterm elections will take place on November 3, 2026. ​A candidate's party will be determined by their ballot-listed or otherwise identifiable affiliation with that party at the time all of the 2026 House elections are conclusively called by this market's resolution sources. A candidate without a ballot-listed affiliation to either the Democrat or Republican parties will be considered a member of one of these parties based on the party with which they most recently expressed their intent to caucus at the time all of the House elections are conclusively called by this market's resolution sources. This market will resolve based on the result of the election as indicated by a consensus of credible reporting. If there is ambiguity, this market will resolve based solely on the official results as reported by the United States government, specifically the Federal Election Commission (https://www.fec.gov/).

Full rules on Polymarket

Kalshi8.4K contracts traded

Prices which party wins.

Mike Bost: Counted · bid 97.0% / ask 97.9% · $1.9K within 5 pts

Contract shown: Mike Bost

If the House member sworn in for IL-12 for the term beginning in 2027 is a member of the Republican Party, then the market resolves to Yes.

This market is eligible for accelerated determination after a consensus of media organizations project the winner. See full rules for details.

Full rules on Kalshi

Also in Illinois

  1. Illinois SenateD98%
  2. Illinois GovernorD97%
  3. IL-01 HouseD96%
  4. IL-02 HouseD96%
  5. IL-03 HouseD96%
  6. IL-04 HouseD96%
  7. IL-05 HouseD97%
  8. IL-06 HouseD97%