The open NY-21 seat, vacated by retiring Republican Rep. Elise Stefanik, features Republican Anthony Constantino, a self-funding Sticker Mule CEO who won his June primary with Trump backing, against Democrat Blake Gendebien, a dairy farmer and first-time candidate. The district's Republican lean—rooted in voter registration advantages and Trump’s prior margins—supports Constantino’s 69.5% trader-implied probability, reinforced by his roughly $17 million in personal spending on advertising and a final-day visit from Vice President JD Vance. Gendebien’s 31.5% share reflects Democratic super PAC investments exceeding $1.7 million, stronger favorability ratings in Siena polling, and targeted appeals on affordability, rural healthcare, and farming issues that narrowed some late surveys to within a few points. Forecasters rate the race Lean or Likely Republican, with the outcome hinging on turnout among the district’s conservative base on November 3.