Tools chosen: kalshi_direct kalshi_related polymarket_related claude_news gdelt_news wikipedia code_execution

Sub-questions (Fermi decomposition)

Planner reasoning

This is a long-horizon Kalshi political market on Marco Rubio being the 2028 GOP VP nominee, which depends on who wins the 2028 GOP presidential nomination and whom they pick. The market price is the primary anchor, supplemented by cross-venue Polymarket pricing on the same and related markets (Rubio as presidential nominee, VP nominee field) and news on Rubio's 2028 positioning, including Trump/Vance signaling.

# Current state Rubio is Secretary of State and acting National Security Advisor; no 2028 GOP ticket has been formed and no candidate has formally declared. Kalshi currently prices Rubio as VP nominee at 28% YES, while a separate Kalshi market prices him as the presidential nominee at 22% — both reflect speculation only, not any binding intra-party decision (primaries haven't started, no dates set per Wikipedia). # Timeline of key events - 2025-01: Rubio confirmed as Secretary of State; 2025-05-01 also named acting National Security Advisor (confirmed, Wikipedia). - 2025-10: Trump calls a Vance-Rubio 2028 ticket "unstoppable" (reported, The Hill). - 2025-12: Rubio tells Vanity Fair he'd support Vance if Vance runs for president (reported, TIME). - 2026-04: Harvard CAPS/Harris poll shows Vance 48% vs. Rubio 16% among Republicans for 2028 nomination (reported). - 2026-05: Trump discusses Vance vs. Rubio 2028 ticket publicly; calls Vance "most likely" heir apparent (reported, TIME/Deccan Herald). - 2026-06: Trump calls Vance-Rubio a "dream team"; Vance deflects, says he'll discuss 2028 only after 2026 midterms (reported, TIME/Yahoo). - 2026-06 (~CPAC straw poll, reported later): Rubio finishes close second to Vance (reported, Fox News, ~2026-07). - 2026-07: Reports say Rubio "sees the writing on the wall" as Vance ponders a bid; a major GOP donor reportedly backs Vance over Rubio (reported, Rawstory/Daily Beast). - 2026-08-06: Reports Trump privately urges donors to back Vance for 2028 (reported, multiple iHeart affiliates, same underlying story). - 2026-08-20/21: New poll shows Rubio outperforming Vance in hypothetical general-election matchups vs. Newsom/Harris/AOC (reported, NY Post/AOL) — distinct from primary/VP standing. # Event Will Marco Rubio be the 2028 Republican VP nominee (accept the nomination if selected)? # Outcomes to forecast Yes / No # Kalshi market anchor KXVPRESNOMR-28-MR (Rubio VP): **28% YES**, down 1pt over 7 days, flat over 30 days, range 22–45% over 80 days, avg volume 764 contracts/day. This is the primary consensus to beat. # Sub-question answers 1. **Current Kalshi price/90-day trend** — 28% YES currently; 7-day -1pt, 30-day flat; has ranged 22–45% over the observed window, implying meaningful volatility earlier that has settled recently (kalshi_direct). 2. **Polymarket comparison** — No matching active Polymarket markets found for Rubio VP, Rubio president, or Vance 2028 (polymarket_related); no cross-market check possible. 3. **P(Vance wins 2028 GOP nomination)** — No direct Kalshi/Polymarket price found; code_execution's decomposition model assumes ~45–60% (midpoint ~52%) based on polling dominance (Harvard CAPS/Harris: Vance 48% vs Rubio 16%) and Trump's repeated public framing of Vance as "most likely" successor (claude_news). 4. **Rubio's signaled intent vs. Trump/Vance statements** — Rubio has repeatedly deferred, saying Vance "would be a great nominee" and that he wants to keep his current job "as long as the president allows" (Fox News); told Vanity Fair he'd support a Vance run. Trump has floated a Vance-Rubio ticket as "unstoppable"/"dream team" multiple times but has not fully endorsed either as successor; Vance deflects 2028 questions, deferring discussion until after 2026 midterms (claude_news). 5. **Historical base rate for VP speculation ~3 years out** — Not directly addressed by research tools; no historical dataset was returned. Qualitatively, VP speculation this far out (Bentsen, Kemp, Palin-precursor chatter) has a low hit rate historically since running mates are typically chosen close to the convention and depend heavily on who the nominee is. 6. **Effect of Sec. State/NSA role** — Not explicitly analyzed by sources; Wikipedia confirms Rubio holds a rare dual Secretary of State + acting NSA role (last held by Kissinger), which raises his profile/stature but PBS/AP reporting frames Rubio and Vance as jostling/rival power centers on national security policy, suggesting tension rather than a clear VP boost (PBS/AP via claude_news). # Key facts (high-confidence, factual) 1. [Kalshi] Rubio VP nominee market: 28% YES, 80-day range 22-45%. 2. [Kalshi related] Rubio presidential nominee market: 22% YES (30-day -9pts); Vance-Kirk ticket market: 9.4% (30-day +5.4pts). 3. [Wikipedia] Trump constitutionally barred from running for president or VP in 2028; no primary dates set yet. 4. [Wikipedia] Rubio holds dual Sec. of State/acting NSA role since May 2025. 5. [claude_news] Neither Vance nor Rubio has formally announced a 2028 candidacy as of mid-2026. # Cross-market signals - Kalshi related: Rubio-as-president (22%) < Rubio-as-VP (28%), suggesting market sees VP slot as more likely path than top of ticket; Vance-Kirk specific ticket only 9.4%, implying market spreads probability across many possible Vance running mates. - Polymarket: No active markets found — no independent cross-check available. - Sportsbook implied: None found. # Analyst opinions and speculation - Code_execution decomposition model: ~12.7% central estimate (range 7–20%) using P(Vance nominee)×P(Vance picks Rubio) + P(other nominee)×P(picks Rubio). This is meaningfully below Kalshi's 28%. - The same tool's "de-vigged market" calculation (5-8%) used **illustrative/fabricated quotes, not the real 28% Kalshi price** — this sub-analysis should be disregarded as it materially misrepresents the actual market anchor. - Reporting (Daily Beast, Rawstory) suggests donor class increasingly favoring Vance over Rubio for the top slot, and Rubio "seeing the writing on the wall," consistent with Rubio settling into a VP-track narrative rather than presidential frontrunner. # Directional lean per outcome - **Yes (Rubio VP)**: Supported by repeated Trump "dream team" framing, Rubio's explicit deference to Vance, Rubio's high public profile/stature (Sec. State + NSA), and market pricing him higher for VP (28%) than president (22%). Opposed by: no formal decision process has begun, Vance himself hasn't secured the nomination, multiple other names (DeSantis, Cruz, Paul, Trump Jr., Carlson) remain in the mix, and 3-year-out VP speculation is historically unreliable. - **No**: Supported by structural uncertainty (~3 years to convention, no declared candidates, running-mate choice usually depends on eventual nominee's needs for balance which may not favor a fellow Trump-administration Floridian), reported Vance-Rubio rivalry/jostling, and decomposition modeling well below Kalshi price. # Gaps / unknowns - No live Polymarket comparison available. - No explicit market price for "Vance wins 2028 nomination" was retrieved directly — only inferred from polling and Kalshi-adjacent decomposition. - No historical base-rate dataset for early VP speculation was returned. # Calibration anchors - Kalshi current YES price: **28%** (primary anchor). - Decomposition model central estimate: ~12.7% (range 7-20%) — meaningfully lower than Kalshi, flagging possible overpricing of Rubio VP odds, or model underweighting Trump's explicit "dream team" endorsements. - Historical precedent: VP nominees are rarely locked in ~3 years pre-convention; high base-rate uncertainty favors wide error bars around any point estimate.

1. Both forecasts converge tightly (0.20/0.23) despite acknowledging a decomposition model (~12.7%) that is materially lower than Kalshi (28%) and enormous structural uncertainty (~3 years out, no declared candidates); given the brief's explicit warning that "VP nominees are rarely locked in ~3 years pre-convention" with "wide error bars," neither forecast reflects that uncertainty in their point estimates or confidence levels (0.55/0.52 seem oddly precise for such a speculative event). 2. Neither forecaster explores the scenario where Rubio himself becomes the presidential nominee (priced at 22% on Kalshi) — if that happens, P(Rubio VP)=0 by definition, yet neither explicitly nets this out of their calculation; the decomposition should account for P(Rubio is nominee)×0 + P(Vance is nominee)×P(picks Rubio) + P(other nominee)×P(picks Rubio), and it's unclear if the 22% presidential probability was properly excluded from the "other nominee" bucket. 3. Both forecasters underweight the tail scenario where health, scandal, or Trump's own preference shifts dramatically change the field over 3 years (e.g., a Rubio scandal, Vance flame-out, or emergence of a new favorite like Vance-Kirk which already shows momentum at 9.4% and +5.4pts over 30 days) — this ticket-specific market movement suggests the race is more fluid than either forecast's static framing implies. 4. The brief notes reported "Vance-Rubio rivalry/jostling" over national security policy (PBS/AP) as a factor against pairing them, but neither forecast weighs this substantively — if Vance wins the nomination, tension with a rival power center could make him less likely to choose Rubio as running mate, potentially pulling the "P(Vance picks Rubio)" conditional probability lower than the 20-25% both implicitly assume. 5. Both forecasts settle just below Kalshi (20% and 23%) without independently justifying why the anchor should shift by only ~5-8 points rather than more fully toward the decomposition model's ~13% midpoint or holding closer to the 28% anchor — this "split the difference" approach isn't well-justified given the evidence brief flags the decomposition model as potentially "underweighting Trump's explicit 'dream team' endorsements," which could argue for staying closer to 28% rather than converging near 20-23%. 6. Neither forecast explicitly addresses the CPAC straw poll result (Rubio finishing "close second to Vance") which is a stronger signal of GOP base preference than the Harvard poll's 48-16 gap, and could suggest Rubio has more viability as either a presidential or VP contender than the decomposition model's heavy reliance on the Harvard poll implies.

22% (54% confidence)

Yes: 22% No: 78%

Kalshi's 28% is the primary anchor but is a thin, long-dated market (764 contracts/day, 3 years to the convention) that plausibly overprices name recognition and Trump's rhetorical 'dream team' framing. A cleaner decomposition — P(Rubio is himself the presidential nominee, ~20%, which zeroes out the VP path) + P(Vance nominee ~50%) x P(Vance picks Rubio ~20-25%, discounted by reported Vance-Rubio national-security jostling and donor consolidation behind Vance) + a small path via other nominees — lands near 13-16%. Offsetting upward: Trump has repeatedly and publicly floated Vance-Rubio, Rubio has explicitly deferred to Vance rather than competing, he finished a close second in the CPAC straw poll, and the market itself prices him higher for VP (28%) than president (22%), indicating genuine VP-track positioning. Historically, running mates are chosen weeks before the convention based on the eventual nominee's balancing needs, so any named individual three years out carries a low hit rate. I land at 22% — below the market anchor but above the pure decomposition, with wide error bars acknowledged.

Total pipeline time: 215.3s