The open seat in Illinois’s 9th District, vacated by longtime Democrat Jan Schakowsky, features Democratic nominee Daniel Biss against Republican John Elleson. Trader odds cluster on Democratic margins of 40-50 percent because the district has delivered consistent double-digit Democratic advantages in recent cycles and carries solid-D ratings from multiple forecasters. Biss’s primary victory and ongoing fundraising contrast with Elleson’s minimal campaign resources, reinforcing expectations of a sizable but not overwhelming victory margin three weeks before the November 3 general election. Limited late-cycle polling or unexpected events could still adjust the exact range within the favored buckets.