Illinois 4th District
Currently held by a Democrat · open seat
Democrat
Patty Garcia
94%
Republican
Lupe Castillo
6%
ForecastLikely D
- Projected margin
- D+26.4
- 80% range
- D+5.1 to D+47.7
- Partisan lean
- D+33.7
- Tipping-point chance
- 0.22%
- Uncertainty multiplier
- 3.00×
The 80% range comes from 200,000 simulations in which this race’s error is correlated with every other race through the national, state and demographic layers.
How the estimate is built
41%59%
Polls 41%Fundamentals 59%
- Polling average
- D+19.0
- Fundamentals
- D+48.1
- Blended
- D+27.0
- Similar-race shift
- −0.5
- Poll–fundamentals gap
- 29.1 pts
PollingDR matchup
- Polls in window
- 1
- Distinct pollsters
- 1
- Most recent
- August 4, 2026
- Democrat
- 34.0%
- Republican
- 15.0%
- Undecided / other
- 38.0%
- Spread between polls
- 0.0 pts
Fundamentals
- Partisan lean
- D+33.7
- Elasticity
- 1.15
- Incumbency
- 0.0
- Candidate experience
- 0.0
- Fundraising
- +4.5
- National environment
- D+5.4
- Expected margin
- D+48.6