JD Vance holds the top position in this open 2028 field at 20.8 percent amid his strong standing as sitting vice president and consistent leads in early Republican primary polling averages near 39 percent. The Democratic side remains fragmented, with no candidate exceeding low double digits on prediction markets despite Harris topping some primary surveys, allowing AOC, Ossoff, Newsom, and others to draw support based on name recognition and positioning ahead of formal declarations expected after the November midterms. Recent Republican convention activity featuring Vance and scattered Democratic maneuvering have reinforced these early dynamics without yet producing separation. Trader pricing reflects this uncertainty in an incumbent-free race, where primary performance, general-election head-to-head polling trends, and post-midterm shifts could quickly reorder the field.