Incumbent Democrat Sean Casten secured his party's nomination in the March 2026 primary with roughly three-quarters of the vote against a single challenger. The district, encompassing southwest Chicago suburbs and eastern DuPage County areas, has leaned Democratic in recent cycles, with Casten winning reelection in 2024 by a double-digit margin. Trader consensus reflected in the 93.8% Democratic probability aligns with the district's partisan composition, Casten's established fundraising edge, and the absence of competitive Republican primary developments. A Republican upset would likely require unusually high GOP turnout, a major national political shift favoring Republicans, or unforeseen issues affecting the Democratic nominee before November 3.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · UpdatedIL-06 House Election Winner
$39,638 Vol.
$39,638 Vol.
Democratic Party
94%
Republican Party
3%
$39,638 Vol.
$39,638 Vol.
Democratic Party
94%
Republican Party
3%
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 Democrat Sean Casten secured his party's nomination in the March 2026 primary with roughly three-quarters of the vote against a single challenger. The district, encompassing southwest Chicago suburbs and eastern DuPage County areas, has leaned Democratic in recent cycles, with Casten winning reelection in 2024 by a double-digit margin. Trader consensus reflected in the 93.8% Democratic probability aligns with the district's partisan composition, Casten's established fundraising edge, and the absence of competitive Republican primary developments. A Republican upset would likely require unusually high GOP turnout, a major national political shift favoring Republicans, or unforeseen issues affecting the Democratic nominee before November 3.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · Updated
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