Pennsylvania state Treasurer Stacy Garrity stands as the only Republican candidate appearing on the May 19 primary ballot for governor, supported by the state party’s early endorsement and President Trump’s backing. Former nominee Doug Mastriano’s January withdrawal from a formal run left a clear path, with his supporters mounting a write-in effort that traders view as structurally disadvantaged by filing deadlines, limited ballot visibility, and historical low success rates for such campaigns in Pennsylvania. This positioning has produced overwhelming market consensus for Garrity’s nomination. Potential shifts remain possible only through unusually high write-in participation or last-minute turnout surges on primary day, though these outcomes have rarely altered results in comparable state contests.