Brazil 2026 presidential first round — runoff triggered, locked at 88%.

88% probability no candidate exceeds 50% in Brazil's Oct 4 2026 presidential first round, triggering the Oct 25 runoff. Lula leads at ~39-42% in mid-2026 polling; the leading challenger polls significantly lower. Scored against the TSE official first-round result. Non-partisan.

Type · Prediction Lock · calibrated binary · non-partisan Locked · 2026-06-21 · Brazil presidential first round Oct 4 2026 Resolves · 2026-10-04 · Tribunal Superior Eleitoral (TSE) official first-round results Scored · binary: no candidate exceeds 50% → runoff triggered yes/no

Lula first-round polling (mid-2026 aggregate)

~39–42%

no candidate near 50% · TSE official result · runoff Oct 25

Brazilian polling aggregates (mid-2026): Lula leads at ~39-42%; the leading challenger polls significantly below 50%. No candidate is close to the absolute majority threshold required to avoid a runoff. Scored against the Tribunal Superior Eleitoral (TSE) official first-round certified result, Oct 4 2026. Non-partisan framing: criterion is a mathematical threshold only — no characterisation of any candidate. The specific second-place candidate is not named as the field is unsettled at lock date.

— 1 · The Locked Call

No candidate exceeds 50% in Brazil's Oct 4 first round — runoff triggered — P = 0.88.

We lock a binary claim: No candidate receives more than 50% of valid votes in Brazil's October 4 2026 presidential first round, per the Tribunal Superior Eleitoral (TSE) official first-round results — triggering the October 25 2026 runoff. Confidence 88%. Non-partisan framing: the criterion is a mathematical threshold; no candidate is named or characterised beyond the vote-share figure.

— 2 · Why it's nail-able

Lula ~39–42%; no candidate near 50%; TSE official result is the definitive unambiguous source.

Brazilian polling aggregates as of mid-2026 show Lula leading at approximately 39-42% in first-round voting intention, with no other candidate polling near the 50%+1 absolute majority threshold required to avoid a runoff under Brazil's constitution. Brazil's last competitive two-cycle election (2022) ended in a runoff with Lula at ~48% in the first round — a candidate surpassing 50% outright in the current fragmented field would be a structural break. Resolves against the Tribunal Superior Eleitoral (TSE) official first-round certified results published on or after October 4 2026. Non-partisan: RAOSCAFF expresses no political preference; the leading challenger is referred to generically as the field is unsettled at lock date.

Locked on 2026-06-21 — scored against TSE official first-round results, Oct 4 2026. Non-partisan.

RAOSCAFF locks P-59 on 2026-06-21. Criterion is mathematical (50% threshold); non-partisan throughout. Resolution: TSE official first-round result.

Locked: 2026-06-21 (commit timestamp on origin/main)
Resolves: 2026-10-04 — Tribunal Superior Eleitoral (TSE) official first-round results (tse.jus.br)
Source: TSE (Tribunal Superior Eleitoral) official first-round presidential election results
Scored by: Binary: YES if no candidate receives >50% of valid votes in the first round (runoff triggered); NO if any candidate exceeds 50% (no runoff)

Non-partisan: criterion is a vote-share threshold only — RAOSCAFF expresses no political preference and does not characterise any candidate.