The Forecasting MachineOpen interactive report

Will Jeff Merkley (D) win the Oregon U.S. Senate election on November 3, 2026?

Resolves Yes if Jeff Merkley (D) is certified as the winner of the Oregon U.S. Senate seat contested on November 3, 2026, and No otherwise. If the contest is not decided on election night — because of a runoff, a ranked-choice tabulation, or a recount — it resolves on the final certified result. Declared candidates: Jeff Merkley (D); David Brock Smith (R).

Forecasted on

Forecast probabilities

  • Yes: 98.1%
  • No: 1.9%

Reasoning

Merkley is overwhelmingly favored: the forecast is Yes, 98.1%, and No, 1.9%. Oregon’s partisan history, Merkley’s record, his financial advantage and a favorable national environment all point the same way; the remaining uncertainty reflects the lack of race-specific polling and the possibility of unexpected events.

Yes — 98.1%: The fundamentals favor the incumbent

The strongest signal is the state’s track record. Oregon has not elected a Republican senator since 2002, and Merkley won his last two reelections by 19 and 17 points. Cook rates the seat Solid Democratic and puts Oregon’s partisan lean at D+8 [a1, a5, a8]. Merkley also won his primary overwhelmingly, while Republican David Brock Smith received only 29.5% in a crowded primary—hardly a demonstration of consolidated enthusiasm [a1, a3].

The resource gap is unusually large. Merkley had about $6.8 million in cash on hand, compared with less than $30,000 for Smith, who had raised about $121,000 [e1, e6]. The national backdrop also favors Democrats: late-October generic-ballot surveys show Democratic advantages of roughly four to nine points, while several polls report low approval for President Trump [e115, e116, e117, e118, e119, e120]. Independent voters are leaning Democratic nationally, too [e77]. These are not Oregon Senate polls, but they offer no evidence of a Republican wave that would put a D+8 state incumbent in immediate danger.

There are reasons to take Smith seriously: he is an experienced state legislator, and the 2022 Oregon governor’s race was close. Fox News also moved its rating of this Senate contest from Likely Democrat to Lean Democrat [a3, a4] [e5]. But those are counterweights, not proof of a close Senate race. The available sources contain no independent head-to-head polling showing Smith within striking distance [a1, a3].

No — 1.9%: A narrow path, with most risk in what is not measured

The strongest case for a loss is that the race may be closer than the fundamentals imply. Oregon’s recent gubernatorial result showed that statewide Republican support can be competitive, and Fox’s rating change is a warning against treating the outcome as literally certain [a3, a4] [e5]. The absence of public head-to-head polling leaves room for an unexpected local dynamic or a substantial polling miss.

Early ballot returns are another possible source of concern, but not strong evidence of a shift: Republicans had returned slightly more ballots than Democrats and other party-affiliated voters, while only about 16% of registered voters had returned ballots. That snapshot does not establish how the electorate will vote [e102, e114]. Nor does the warning that a three-point polling error could reshape national control establish that Oregon’s Senate race is close [e95].

The administration’s planned election monitoring in Multnomah County and a layout error in the voters’ pamphlet add noise around the process, but the reporting does not show that either changes the likely vote count or outcome [e75, e76] [e50]. Merkley’s earlier hesitation about seeking another term is a possible vulnerability, though he ultimately committed to running; the available reporting identifies no scandal or health issue threatening his candidacy [e2] [a1, a8].

Why the forecast is so lopsided

The evidence is not equally informative. Oregon’s long Democratic record, Merkley’s prior margins and his overwhelming financial advantage are durable indicators; a rating downgrade and an early-return snapshot are weaker and more ambiguous. The August market price near 98% is a useful cross-check, not a substitute for polling [e7]. With no direct poll showing a competitive race and no identified event that would overturn the structural advantages, the balance supports Yes at 98.1%, while reserving 1.9% for No to reflect genuine uncertainty.

Update summary

Fresh national polls continue to show Democrats leading the generic ballot, broadly reaffirming the environment already reflected in the forecast [e115, e118, e119]. No new Oregon Senate-specific evidence has emerged, and the latest ballot-return figures repeat an earlier snapshot [e102, e114].

Cited evidence