**U.S. Rep. Tom Tiffany's 87.5% implied probability as the Republican primary winner for Wisconsin governor reflects strong party unity following President Trump's late January 2026 endorsement, which prompted rivals like Josh Schoemann to drop out and cleared the field of major challengers.** Major donors including the Uihleins and Diane Hendricks back Tiffany, alongside grassroots conservatives, positioning him as the consensus frontrunner in the open-seat race after Gov. Tony Evers' retirement. Recent March-April polls and commentary highlight his authentic Wisconsin appeal and policy alignment, with no significant momentum for Tommy Thompson or longshots like Sean Duffy and Rebecca Kleefisch. The August 11 primary looms, but traders see minimal barriers to Tiffany's nomination absent late entrants or scandals.