Tools chosen: kalshi_direct kalshi_related polymarket_direct polymarket_related claude_news gdelt_news wikipedia code_execution

Sub-questions (Fermi decomposition)

Planner reasoning

This is a very long-horizon Kalshi market on who wins the 2028 US presidential election, with Marco Rubio as one of many candidates. The market price is the primary anchor; cross-venue comparison with Polymarket (which has a liquid 2028 presidential winner market) is the key independent signal. Secondary research: Rubio's current standing in 2028 GOP primary polling, Trump endorsement signals, and the field structure (Vance is the frontrunner).

# Current state Marco Rubio's Kalshi contract (KXPRESPERSON-28-MRUB) currently prices him at 13% to be the next inaugurated president, down from a 90-day high of 20% and drifting lower over the past month. The GOP nomination is undecided; JD Vance leads most polling and prediction markets, but Rubio has shown recent momentum in select polls without any formal campaign announcement from either man. # Timeline of key events - 2025-01-21 (confirmed): Rubio sworn in as Secretary of State; later also acting National Security Advisor (Wikipedia). - 2026 (unspecified, reported): RealClearPolitics aggregate had Vance ~45.5%, Rubio ~14% in GOP primary polling (zerohedge.com, pre-Rubio surge). - 2026-05 (reported): Emerson College poll shows Vance 36%, Rubio 35% among GOP primary voters — near-tie (claude_news). - 2026-07-10 (reported): "White House insiders" say Rubio "sees the writing on the wall" as Vance ponders bid (rawstory.com). - 2026-07-23/24 (reported): New Hampshire GOP primary poll (UNH) shows Rubio surging from 7% to 26%, still trailing Vance 36%-26% (foxnews.com, el-balad.com). - 2026-08-06 (reported): Trump privately urges donors to back Vance for 2028 (multiple iHeart affiliates, same wire story). - 2026-08-07/08 (reported): Trump says "too early" to anoint a successor; Rubio gets polling boost; Trump calls Vance succession "not set in stone" (townhall.com, gazette.com). - Mid-April (year unclear) (reported): Echelon Insights poll shows Vance 42%, Rubio 14% — wide gap, contradicts NH surge trend. - Undated (reported): Western Conservative Summit straw poll — Rubio 57% vs. Vance, a 36-point Rubio lead among conservative activists (thehill.com) — likely an outlier/unrepresentative sample. # Event Will Marco Rubio be the person inaugurated as U.S. President in January 2029 (KXPRESPERSON-28-MRUB)? # Outcomes to forecast Yes / No # Kalshi market anchor **Current YES price: 13%** (down from 90-day high of 20%; -1pt over 7 days, -5pts over 30 days). Average daily volume ~13,414 contracts — this is a liquid, actively-traded market and should be treated as the primary consensus. Trend is modestly declining. # Sub-question answers 1. **Current Kalshi YES price/trend** — 13% currently; range 12-20% over 90 days; declining trend (-5pts/30d). [kalshi_direct] 2. **Polymarket implied probability** — No Polymarket market found for this specific contract or related 2028 presidential keywords; no comparison possible. [polymarket_direct/related] 3. **Rubio vs. Vance primary polling** — Mixed/volatile: RCP aggregate has Vance far ahead (~45.5% vs Rubio ~14%); Emerson shows near-tie (36% vs 35%); UNH shows Vance 36% vs Rubio 26% (up from 7%); Echelon shows Vance 42% vs Rubio 14%. Vance is the consistent polling leader; Rubio is a strengthening but clear #2. [claude_news, gdelt_news] 4. **Republican vs Democrat implied win probability** — Kalshi KXPRESPARTY-2028-R prices Republican at 41% (down slightly over 30 days), implying Democrat ~59% (raw, pre-devig; sum of R+D likely ~100-102%). [kalshi_related] 5. **Trump/GOP endorsement signals** — No formal Trump endorsement of either Vance or Rubio; Trump has called Vance "most likely" heir but hedged, floated a joint Vance-Rubio ticket, and privately urged donors toward Vance (Aug 2026) while also saying it's "not set in stone." Rubio has repeatedly said he'd defer to/back Vance if Vance runs, and has not announced independent 2028 intentions, though he hasn't ruled it out ("you never know what the future holds"). [claude_news, gdelt_news] 6. **Base rate for cabinet-level/second-tier contenders winning presidency** — Historically low; sitting Secretaries of State rarely become president directly from the role, and mid-single-digit-to-teens polling contenders this early in a cycle win only a small fraction of the time (rough 5-15% base rate per code_execution estimate). [code_execution, general historical knowledge] 7. **Vig / de-vigged Rubio probability** — Kalshi's own related-market data (not code_execution's illustrative sandboxed figures) has Rubio at 13% raw; the code_execution tool used illustrative/non-live numbers (Rubio 6¢, sum 103¢) that conflict with live kalshi_direct data (13%) — treat code_execution's absolute figures as unreliable, but its qualitative framing (modest overround, Rubio in second tier) is directionally useful. [code_execution — flagged as illustrative, not live] # Key facts (high-confidence, factual) 1. [Wikipedia] Trump is constitutionally barred from a third term; 2028 GOP field is open for the first time since 2012. 2. [kalshi_direct] Rubio YES price: 13%, down from 20% peak in past 90 days. 3. [kalshi_related] Rubio's GOP nomination contract (KXPRESNOMR-28-MR) trades at 22%, down 9pts over 30 days. 4. [kalshi_related] Rubio's VP nomination contract trades at 28%. 5. [kalshi_related] Republican party win contract at 41%. 6. [claude_news] Rubio has publicly said he would defer to/back Vance for the nomination. # Cross-market signals - Kalshi related: Rubio nomination odds (22%) exceed his presidency odds (13%), consistent with discounting for a competitive general election even if nominated. GOP party-win market (41%) implies Democrats favored overall. - Polymarket: No data available for direct comparison. - Sportsbook: Oddschecker lists Vance +508, Newsom +567, Rubio +602 (general election outright), roughly consistent with Rubio trailing Vance but competitive with top Democrats for outright odds — implied probability ~14% for Rubio, roughly matching Kalshi's 13%. # Analyst opinions and speculation - ABC News reports GOP donors quietly plotting a "draft Rubio" 2028 effort, suggesting elite-level hedging against a Vance-only path. - ZeroHedge and Newsweek framed Rubio as a possible "new heir apparent," though this reflects momentum narratives more than settled fact. - Straw poll showing Rubio +36 over Vance among conservative activists is likely unrepresentative (self-selected, small n=500) and conflicts with broader polling/market consensus favoring Vance. # Directional lean per outcome - **Yes (Rubio wins)**: Supported by recent polling momentum (NH surge, Emerson near-tie), donor interest, straw-poll enthusiasm, no ruled-out candidacy. Opposed by Vance's structural VP-incumbency advantage, lack of Trump endorsement for Rubio specifically, Rubio's own deferential statements, and declining Kalshi price trend. - **No (Rubio does not win)**: Favored by market consensus (87% implied No), Vance's polling/market lead, GOP overall ~41-47% win probability meaning Rubio must both win nomination AND general election, and historical base rates disfavoring non-incumbent cabinet officials. # Gaps / unknowns - No neither candidate has formally declared; entry timing/exit of Vance could sharply reprice Rubio. - Polymarket comparison unavailable — cannot cross-check for arbitrage/divergence. - code_execution's quantitative devig analysis used illustrative (non-live) numbers inconsistent with the real Kalshi price (13% vs. implied 6¢) — do not rely on its absolute figures. - Unclear whether Trump will eventually make an explicit endorsement before primaries begin. # Calibration anchors - Kalshi current YES price: **13%** (primary anchor). - Sportsbook-implied ~14% (Oddschecker) — close alignment with Kalshi, suggesting reasonably efficient pricing. - Historical base rate for similarly-positioned cabinet-level contenders/second-tier candidates this early: ~5-15%, roughly consistent with current market pricing.

1. Both forecasts converge tightly around 11-12%, essentially just shading the 13% Kalshi anchor slightly downward for similar reasons—this convergence masks the fact that neither seriously grapples with the wide divergence in cross-market signals (nomination contract 22% × GOP win 41% = ~9%, vs. raw Kalshi 13%, vs. sportsbook 14%), which could justify a broader range or more decisive resolution of which signal to trust rather than splitting the difference cosmetically. 2. Neither forecast adequately addresses the timing/gap risk explicitly flagged in the brief: "entry timing/exit of Vance could sharply reprice Rubio." If Vance stumbles, exits, or is forced out (health, scandal, Trump souring further), Rubio is the most obvious beneficiary given "draft Rubio" donor chatter and straw-poll enthusiasm — this tail scenario deserves explicit mention rather than being folded into a static point estimate three years before the election. 3. Both treat the nomination-contract-times-general-election-multiplication (22% × ~45% ≈ 9-10%) as a "cross-check" pulling the estimate down, but this arithmetic double-counts uncertainty already priced into the direct 13% market and ignores that Rubio's VP-nomination contract (28%) is higher than his presidential-nomination contract (22%), suggesting the market sees a real path via VP-to-President succession/incumbency that neither forecaster models explicitly (e.g., Vance picks Rubio as VP, then Rubio succeeds later or runs 2032 — though that's outside this window, a 2028 VP slot with Trump stepping back could still create relevant scenarios). 4. Neither forecaster discusses the extremely long time horizon (event closes Nov 2029, over 3 years out) and how that should widen uncertainty bands rather than just anchoring tightly to a currently volatile, thinly-substantiated market (13% price has swung from 20% to 12% in 90 days) — high volatility this early should arguably argue for a wider confidence interval or explicit acknowledgment of low informational value at this stage, not just fine-tuning to the nearest percentage point. 5. Both forecasts under-weight the contradictory straw-poll and Emerson data as mere noise, but neither considers that Rubio's polling volatility (7%→26% in NH, 14%→35% in Emerson within short windows) could reflect a genuine emerging trend rather than pure noise, warranting a slightly higher point estimate or at least a wider stated uncertainty rather than confidently settling just below market consensus. 6. Confidence levels (0.60, 0.64) are stated without clear justification for what "confidence" means in the context of a market-anchored point estimate — given the brief's own acknowledgment that Polymarket comparison is unavailable and code_execution's quantitative devig figures were flagged as unreliable, both forecasters express moderate-high confidence that seems inconsistent with the acknowledged data gaps and this far out from the actual election.

12% (62% confidence)

Yes: 12% No: 88%

The liquid Kalshi contract (13%) and Oddschecker (~14%) agree closely, while the structural decomposition (22% nomination × ~41-45% GOP general win ≈ 9-10%) argues modestly lower; rather than mechanically averaging, I note the decomposition partially double-counts and that longshot bias typically inflates raw person-market prices, leaving a fair value just under the anchor. Vance remains the consistent polling and market leader with VP-heir advantages and Trump quietly steering donors his way, and Rubio has publicly said he would defer — but the horizon is three years, Rubio's polling has genuinely surged in some surveys (NH 7%→26%, Emerson near-tie), donors are floating a 'draft Rubio' effort, and a Vance stumble would make Rubio the obvious beneficiary. That live tail scenario plus the critique's point about excessive precision at this horizon keeps me from shading far below market. Final: 12% Yes, essentially at the market with a small discount for longshot bias, and I acknowledge genuine uncertainty (the price has ranged 12-20% in 90 days).

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