In the non-competitive 2026 Oregon U.S. Senate race, where Democratic incumbent Jeff Merkley faces Republican state Senator David Brock Smith in a contest rated Solid Democratic by forecasters, traders assign nearly identical probabilities across turnout bins from under 1.5 million to over 2.2 million votes. Recent certification of the May primary, which drew a record 1.28 million ballots in a low-stakes contest, provides limited guidance for November general election participation. Key variables include ongoing voter registration trends, party mobilization efforts in a mail-in state, national political climate closer to Election Day, and absence of early general election polling. This equilibrium reflects broad uncertainty, with separation likely to emerge from candidate fundraising, issue salience, or registration data releases in the coming months.