Recent Republican midterm losses and President Trump's November 2026 comments indicating he may not endorse a 2028 successor have widened the nomination field and shifted trader focus toward an open contest. Market prices reflect this uncertainty, with Robert F. Kennedy Jr. leading at 49.0% implied probability as the consensus favorite, ahead of J.D. Vance at 30.8% and Marco Rubio at 18.4%. Ron DeSantis and others trail further back amid positioning by administration officials and governors. No candidate has formally declared, leaving room for late developments such as fundraising trends, primary calendar timing, or additional public statements to influence outcomes before the 2028 convention.