The open-seat race in New York’s 21st Congressional District, following Elise Stefanik’s retirement, features Republican Anthony Constantino facing Democrat Blake Gendebien on November 3. Traders assign Constantino the higher implied probability due to the district’s consistent Republican voting history, his primary victory over establishment-backed Robert Smullen, substantial self-funding exceeding $12 million, and alignment with President Trump. Recent Siena polling from late September to early October showed Gendebien ahead 46-42 percent among likely voters, with better favorability ratings, prompting the Cook Political Report to shift its rating from Solid to Likely Republican. Ongoing campaign attacks, differing issue strengths, and undecided voters contribute to the competitive positioning reflected in current market prices.