Incumbent Republican Rep. Mike Bost, House Majority Leader, secured his party's unopposed nomination in the March 17 Illinois primary for the solidly Republican 12th Congressional District (R+22 Cook PVI), facing Democrat Julie Fortier, who also ran unopposed but trails significantly in fundraising with under $20,000 cash on hand versus Bost's $481,000. Recent primary results and forecasters like Cook Political Report rating the race Solid Republican reflect trader consensus on Bost's commanding position, bolstered by his 74% 2024 general election win and district history favoring GOP by wide margins. While a massive Democratic national wave, Bost scandal, or health issue could shift odds before the November 3 general election, such disruptions remain low-probability barriers.
Experimental AI-generated summary referencing Polymarket data · UpdatedIL-12 House Election Winner
IL-12 House Election Winner
Republican Party
92%
Democratic Party
7%
Republican Party
92%
Democratic Party
7%
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/).
Market Opened: Jan 28, 2026, 11:09 AM ET
Resolver
0x2F5e3684c...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/).
Resolver
0x2F5e3684c...Incumbent Republican Rep. Mike Bost, House Majority Leader, secured his party's unopposed nomination in the March 17 Illinois primary for the solidly Republican 12th Congressional District (R+22 Cook PVI), facing Democrat Julie Fortier, who also ran unopposed but trails significantly in fundraising with under $20,000 cash on hand versus Bost's $481,000. Recent primary results and forecasters like Cook Political Report rating the race Solid Republican reflect trader consensus on Bost's commanding position, bolstered by his 74% 2024 general election win and district history favoring GOP by wide margins. While a massive Democratic national wave, Bost scandal, or health issue could shift odds before the November 3 general election, such disruptions remain low-probability barriers.
Experimental AI-generated summary referencing Polymarket data · Updated
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