2028 Republican Nominee Odds: The Full Field Vs. The Kalshi Market

The 2028 Republican nomination market is one of the biggest political boards on Kalshi: 38 named contracts, about 54.7 million contracts traded, 37.3 million still open. Its Democratic twin carried roughly triple that volume when we scored it on July 30, but this is the board where the market has actually made up its mind: two names absorb 69 of its 98.7 total cents, and everything else trades under 6. We put all 38 names in front of an eight-model AI panel with live data and zero prices, then ran a second round in which every model read the other seven's anonymized reasoning and could revise. The panel agrees with the crowd about who is first. It thinks the crowd has the wrong second.

The Quick Answer

Eight AI models, working price-blind from fetched polling, office, and settlement data, make J.D. Vance the 2028 Republican nominee favorite at a 45.5% blend, above his 39.5-cent Kalshi price. The board's real argument is the next line down: the market holds Marco Rubio at 29.5 cents, and the panel blends him to just 15.5%, a 14-point fade that is the widest gap on the board. Below those two, the panel puts Donald Trump Jr. at 6.0% against 3.75 cents, Ron DeSantis at 5.6% against 5.3, and roughly one chance in nine that the nominee is one of the board's thinnest-priced names or someone not listed at all. The full 38-name board, every seat's number, and the dark horses at least one model refuses to dismiss are all below.

The Market

Venue	Kalshi — a CFTC-regulated event-contract exchange (18+; availability varies by state, as of August 2026)
The Contract	One market per candidate, 38 listed: "If [candidate] wins and accepts the nomination for the Presidency for the Republican party in 2028, then the market resolves to Yes." Kalshi's contract terms define the nominee as the first person to be nominated by the party and to accept; a nominee who later withdrew would still settle Yes, and post-expiration revisions do not count.
The Clock	Markets close early once the party nominates someone and they accept, at the 2028 Republican convention; the listed expiration is November 7, 2028
Depth	About 54.7 million contracts traded across the board, 37.3 million open. The most-traded single contract is not the favorite: Marco Rubio's 4.9 million edges J.D. Vance's 3.8 million, and the Donald Trump contract has traded 3.8 million of its own
Timestamps	Verdicts generated August 1, 2026 (both rounds); prices as of August 1, 2026, from the live order book

This is a neutral, data-driven analysis. It presents every candidate's path identically, advocates for no one, and every electoral fact in it was machine-fetched from the named sources at generation time.

One structural note before the numbers: the 38 listed names are Kalshi's listing choices, not a ballot, and there is no field contract. If someone not on the board is nominated, every listed market settles No. The panel was therefore required to price a bucket for the unlisted field, and its blend put 5.3% there.

How The Panel Read It

Eight models (ChatGPT GPT-5.5, Claude Fable, Claude Opus, Claude Sonnet, Gemini 3.1 Pro, GLM 5.2, Kimi K3, DeepSeek V4) each received the same deterministically fetched data card: the full 38-contract board with its binding settlement language, every candidate's current office or public role pulled live from the congress-legislators dataset and Wikipedia, and all 18 polls of the 2028 Republican primary from the last 90 days of the VoteHub feed, each annotated with its pollster's graded accuracy record. No model saw a market price. Each seat priced the top 25 contracts by market activity individually, plus a combined bucket for the other 13 listed names and a field bucket for anyone unlisted, in one pass summing to 100%. Then each seat read the other seven's anonymized reasoning and could revise; four seats revised, four explicitly held, and the headline blend is the equal-weight average of each seat's final board. These are model estimates, not predictions of fact and not financial advice.

The panel's political outings are publicly graded. At the White House Correspondents' Dinner in July, the Kalshi crowd narrowly beat the panel's best seat on 30 settled markets, and we published the full scorecard either way. Read the gaps below with that humility in hand: when these models split from this crowd, the models are not automatically right.

Two card facts did most of the work. The first is the shape of the polling: J.D. Vance leads 17 of the 18 fetched surveys, usually between 29% and 47%, and the one exception is AtlasIntel, the second-sharpest pollster in the card at a 2.21-point average miss, which has Marco Rubio first at 45% with Vance at 30%. The second is structural, and every seat cited it: the card lists Donald Trump as the 47th president, elected in 2016 and 2024, and the Twenty-second Amendment limits the number of times a person can be elected president to two (verified this run against the amendment's text summary). Eight seats independently concluded they were pricing a race without the party's dominant figure in it.

"A term-limited incumbent's sitting vice president leads 17 of 18 polls by about twenty points, and sitting VPs who seek open nominations historically win them." — Kimi

"I put Donald J. Trump himself at just 2% despite being sitting president: the 22nd Amendment bars election to a third term, and tellingly he appears in NONE of the 18 listed primary polls, consistent with voters treating this as a post-Trump field." — Claude Sonnet

The Revision Round

After round one, each seat read the other seven's reasoning, anonymized, with instructions that revising is optional and conformity is a failure mode. The round split the panel cleanly in half.

Four seats moved, all in the same direction. Gemini raised Vance from its panel-low 34%, writing that the "historical conversion rate of sitting VPs seeking the nomination, combined with his near-universal 15-30 point polling leads, convinced me that my 34% was too heavily discounted for time." ChatGPT lifted Vance from 38 to 43 on the same argument, while noting it would not chase the panel's highest numbers "because the card's own polling note warns that early preference polls are not nomination probabilities." DeepSeek nudged Vance and Rubio both up, and GLM raised Rubio from 13 to 15 after a peer isolated a polling pattern it had missed.

That pattern was the round's one piece of new analysis, and it came from Kimi's first-round board: Rubio spikes to 32-45% precisely in the polls where Donald Trump Jr. is absent or listed at zero, which reads as consolidation capacity rather than committed support. Claude Fable held its topline at 45, and its one substantive move in response was Rubio, 13 to 15, funded from its field reserve, calling the pattern the only new observation on the table.

The four holds were as pointed as the moves. Claude Opus stayed at 57, the panel's high, on the grounds that the shared objections were "the exact terms already sitting in my 13-point FIELD+OTHER_LISTED allocation." Kimi held at 47 and pushed back on that same number, arguing it "compresses the endorsement uncertainty (the one event every forecaster agrees would re-allocate 20-30 points) into near-certainty." And Claude Sonnet held with the round's most honest sentence about the whole exercise: "No peer surfaced evidence outside the card — all eight of us are recombining the same 18 polls and the same VP/22nd-Amendment structural read; the spread (34-57% on Vance) reflects differing risk tolerance for early-polling volatility, not new facts."

J.D. Vance: The Favorite The Panel Likes More Than The Market Does

Every seat's final board has the vice president first, from Gemini's 38.8 to Opus's 57, and the blend of 45.5% sits six points above his 39.5-cent price. The case is the same in every rationale: the vice presidency is the strongest structural platform an open nomination race offers, the polling lead is broad and durable across pollsters with different house effects, and the historical record of sitting vice presidents who actually sought their party's nomination is strong. GLM's round-one file named the precedents: Bush in 1988, Gore in 2000, Humphrey in 1968.

The discounts are just as consistent. Twenty-seven months of exposure is a long time; the environment block in the card (presidential approval 42.2 approve / 55.6 disapprove, generic congressional ballot D+6.4 in the live VoteHub pulse) describes a party defending an unpopular administration; and the card's own coverage note warns that early primary preference this far out has historically translated loosely into nominations. That is why six of eight final boards keep him under 48 despite polling shares in the 40s. What no seat did is treat him as anything but the clear favorite, which makes this one of the rare boards where the panel is more bullish on the front-runner than the money is.

Marco Rubio: The 29-Cent Question

Here is the board's argument. The market holds the secretary of state at 29.5 cents, within touching distance of the favorite and the single most-traded contract on the board. The panel's final blend is 15.5%, and no seat finished above Sonnet's 20. That 14-point gap is the widest disagreement on the board, and it is specifically a disagreement about what his polling means.

The bull case is real and the seats said so: Rubio is the clear, consistent second in nearly every fetched survey, he runs the State Department and is the acting national security advisor per the card, and the sharpest pollster in the set has him outright first. The panel's counter is the conditional structure of those numbers. His strongest readings cluster in the polls with short candidate lists or no Trump Jr. option, which the seats read as him inheriting the non-Vance vote in hypotheticals rather than commanding it now.

"Secretary of State and acting national security advisor, mid-teens median, and he spikes to 32-45% in polls where Donald Trump Jr. is absent or at zero — evidence he consolidates the non-dynasty vote if Don Jr. stays out." — Kimi

The honest read cuts both ways, the same way it did on the Democratic board's widest gap. A market this deep is not parked at 29.5 cents by accident; if traders are pricing succession scenarios, cabinet visibility, or information fresher than the feed's June 14 polling cutoff, the models cannot see it. But if the price is a story about second-choice polling, the panel is saying the polls themselves give that story about half the support the price implies.

Donald Trump Jr. And Ron DeSantis: The Single-Digit Tier

The panel's third and fourth names both run ahead of or level with their prices, for opposite reasons. Donald Trump Jr. blends to 6.0% against 3.75 cents, and the reasoning was uniform: he polls as high as 21-22% (HarrisX, Lord Ashcroft) on name identification, holds no office, and has never run for anything, so the seats priced what Kimi called "the family lane, not the resume." His number is the panel's estimate of an unresolved succession signal, which is also why Kimi refused to cut him in the revision round. Ron DeSantis blends to 5.6% against 5.3 cents, the board's most agreed-upon price: a sitting governor of Florida with a national campaign already run, polling in single digits, priced by both the crowd and the machines as a credible second act rather than a favorite.

Donald Trump himself is the row that needs the settlement language read carefully. The contract settles on nomination and acceptance, not on winning an election, so the Twenty-second Amendment does not mechanically settle it No. The panel's final blend is 1.1% against a 2.55-cent price: the seats' stated reasoning is that a party has no incentive to nominate someone barred from being elected to the office, and that his absence from all 18 fetched primary polls suggests the electorate is not treating him as a choice. Three seats still left him 1.5 to 2.5 points as the residual scenario where the succession never actually resolves.

The Board

Panel blend is the equal-weight average of each seat's final board, after the revision round. Kalshi prices are quote midpoints from the live book, August 1, 2026. Roles were fetched this run from the congress-legislators dataset and Wikipedia. The bottom 13 names were priced by the panel as a single combined bucket (marked †), per the protocol described above.

Candidate	Current Role	Kalshi	AI Blend
J.D. Vance	Vice President (since 2025)	39.5¢	45.5%
Marco Rubio	Secretary of State (since 2025)	29.5¢	15.5%
Donald Trump Jr.	Businessman and political activist	3.75¢	6.0%
Ron DeSantis	Governor of Florida (since 2019)	5.3¢	5.6%
Vivek Ramaswamy	2026 Republican nominee for Ohio governor	0.45¢	2.5%
Ted Cruz	U.S. Senator, TX	1.15¢	2.2%
Tucker Carlson	Host, The Tucker Carlson Show	2.25¢	1.6%
Glenn Youngkin	Former Governor of Virginia (2022-26)	1.05¢	1.3%
Donald Trump	President (2017-21; since 2025)	2.55¢	1.1%
Josh Hawley	U.S. Senator, MO	0.85¢	1.1%
Greg Abbott	Governor of Texas (since 2015)	0.45¢	1.0%
Brian Kemp	Governor of Georgia (since 2019)	0.55¢	0.8%
Sarah Huckabee Sanders	Governor of Arkansas (since 2023)	0.6¢	0.8%
Tulsi Gabbard	Former Director of National Intelligence (2025-26)	0.55¢	0.8%
Tom Cotton	U.S. Senator, AR	0.35¢	0.7%
Rand Paul	U.S. Senator, KY	0.45¢	0.6%
Lara Trump	Former RNC co-chair	0.5¢	0.4%
Steve Bannon	Media executive, War Room host	0.45¢	0.3%
Thomas Massie	U.S. Representative, KY	1.25¢	0.2%
Erika Kirk	Chairwoman and CEO, Turning Point USA	0.45¢	0.2%
Marjorie Taylor Greene	Former U.S. Representative, GA	0.95¢	0.2%
Ivanka Trump	Businesswoman	1.25¢	0.2%
Candace Owens	Political commentator	0.5¢	0.1%
Jeff Bezos	Founder and executive chairman, Amazon	0.5¢	0.1%
Spencer Pratt	Television personality	0.5¢	0.1%
Robert F. Kennedy Jr.	Secretary of Health and Human Services	0.35¢	—†
Pete Hegseth	Secretary of Defense	0.35¢	—†
Byron Donalds	U.S. Representative, FL	0.35¢	—†
Nikki Haley	Former UN ambassador; 2024 candidate	0.35¢	—†
Katie Britt	U.S. Senator, AL	0.25¢	—†
Mike Pence	Former Vice President (2017-21)	0.25¢	—†
Elise Stefanik	U.S. Representative, NY	0.25¢	—†
Eric Trump	Businessman	0.15¢	—†
Elon Musk	Businessman	0.15¢	—†
Kristi Noem	U.S. special envoy; former DHS secretary	0.15¢	—†
Nicki Minaj	Rapper	0.15¢	—†
Matt Gaetz	Former U.S. Representative, FL	0.15¢	—†
John Thune	U.S. Senator, SD	0.15¢	—†
† The 13 names above (combined)	—	3.1¢ total	5.8%
The Field (anyone unlisted)	—	no contract	5.3%

These are model estimates, not predictions of fact and not financial advice. Quotes below 10 cents run in 0.1-cent ticks, so the sub-cent prices are real two-sided books, but the thinnest of them trade on spreads nearly as wide as the price itself.

Every Seat's Round-1 Number

The table below is each seat's independent round-one board, before any model saw another's reasoning; the headline blend above folds in the revision round. Values are percentages; each column sums to roughly 100 with the buckets.

Candidate	Kalshi	Fable	Opus	Sonnet	GPT	Gemini	GLM	Kimi	DeepSeek	R1 Blend
J.D. Vance	39.5¢	45.0	57.0	42.0	38.0	34.0	36.0	47.0	48.4	43.4%
Marco Rubio	29.5¢	13.0	14.0	20.0	15.0	12.0	13.0	15.0	14.1	14.5%
Ron DeSantis	5.3¢	5.5	3.0	6.0	7.0	6.5	9.0	5.3	7.0	6.2%
Donald Trump Jr.	3.75¢	7.0	2.5	8.0	8.5	6.0	5.5	6.3	5.1	6.1%
Vivek Ramaswamy	0.45¢	1.0	1.2	1.0	4.5	3.5	4.5	2.5	3.5	2.7%
Ted Cruz	1.15¢	1.5	0.8	2.0	3.2	2.0	3.5	3.0	3.0	2.4%
Tucker Carlson	2.25¢	1.5	1.0	1.5	2.8	2.0	1.5	2.4	3.0	2.0%
Glenn Youngkin	1.05¢	1.5	0.8	0.7	2.5	3.5	1.5	0.8	1.0	1.5%
Josh Hawley	0.85¢	0.8	0.8	1.0	2.0	2.0	1.5	1.5	2.0	1.5%
Greg Abbott	0.45¢	1.0	0.6	0.7	2.0	2.0	1.5	0.7	1.0	1.2%
Tulsi Gabbard	0.55¢	0.6	0.4	0.5	1.0	1.5	1.0	1.0	2.0	1.0%
Sarah Huckabee Sanders	0.6¢	1.2	0.5	0.4	1.2	2.0	1.5	0.5	0.5	1.0%
Brian Kemp	0.55¢	1.2	0.7	0.5	1.5	1.5	1.5	0.7	0.5	1.0%
Tom Cotton	0.35¢	0.8	0.6	0.5	1.5	1.5	1.0	0.8	0.5	0.9%
Donald Trump	2.55¢	2.5	1.5	2.0	0.3	0.2	0.3	0.2	0.0	0.9%
Rand Paul	0.45¢	0.4	0.3	0.2	1.0	1.0	1.0	0.7	1.5	0.8%
Lara Trump	0.5¢	0.5	0.3	0.3	0.8	0.5	0.8	0.3	0.3	0.5%
Erika Kirk	0.45¢	0.4	0.3	0.2	0.3	0.2	0.2	0.3	0.1	0.3%
Steve Bannon	0.45¢	0.3	0.2	0.3	0.3	0.5	0.3	0.3	0.1	0.3%
Thomas Massie	1.25¢	0.2	0.1	0.1	0.6	0.5	0.2	0.3	0.5	0.3%
Marjorie Taylor Greene	0.95¢	0.4	0.1	0.3	0.4	0.2	0.2	0.1	0.5	0.3%
Ivanka Trump	1.25¢	0.3	0.1	0.1	0.4	0.5	0.3	0.2	0.1	0.3%
Candace Owens	0.5¢	0.2	0.1	0.1	0.2	0.2	0.2	0.2	0.1	0.2%
Jeff Bezos	0.5¢	0.1	0.1	0.1	0.1	0.1	0.2	0.1	0.1	0.1%
Spencer Pratt	0.5¢	0.1	0.0	0.1	0.1	0.1	0.1	0.1	0.1	0.1%
Other 13 listed (combined)	3.1¢	5.5	6.5	8.4	2.9	12.5	9.5	6.2	3.0	6.8%
The Field (unlisted)	no contract	7.6	6.4	3.0	2.0	3.5	4.2	3.5	2.0	4.0%

These are model estimates, not predictions of fact and not financial advice.

What A Nominee Off The Top Of This Board Is Worth

Add the panel's two bucket rows together and the blend says roughly 11%: about one chance in nine that the 2028 Republican nominee is either one of the 13 thinnest-priced names or someone Kalshi has not listed at all. That is materially more open than the market's board reads at a glance, and it was a deliberate position. Fable and Opus, the two seats most bullish on the favorite, also carried the two biggest reserve allocations, on the stated logic that a 27-month runway prices political mortality, not just competition. The market's version of the same humility is quieter: the 38 mids sum to 98.7 cents, so about 1.3 cents of implied probability effectively lives outside the listed field once spreads are accounted for.

Dark Horses The Panel Won't Dismiss

Asked which sub-5% names they would least want to dismiss, the seats kept returning to three, each with a named structural reason from the card rather than a vibe.

Vivek Ramaswamy (0.45 cents, 2.5% blend) was named by six of eight seats, and the reason is a card fact with a date attached: he is the Trump-endorsed Republican nominee for governor of Ohio in the November 2026 election. Win it, and 2028 opens with a young sitting swing-state governor who has already run a national primary. The panel's number is a price on that parlay, Ohio first; his five-times-price gap over the market is the largest proportional disagreement on the board.

Glenn Youngkin (1.05 cents, 1.3% blend) drew the second-most mentions on a timing argument: his Virginia term ended in 2026, so unlike the sitting governors on this board he is already unencumbered, with self-funding capacity from a private-equity career and a swing-state record. Gemini carried him highest at 3.5 in round one.

Erika Kirk (0.45 cents, 0.2% blend) is the deepest cut, named by Opus and Sonnet on the same fact: since her husband's assassination in September 2025 she has chaired Turning Point USA, one of the largest grassroots conservative organizing networks in the country, with no poll presence at all. The tiny number is the point: it is the panel flagging an organizational platform the polling cannot see yet.

One market-side footnote the panel could not weigh in on individually: Robert F. Kennedy Jr., the sitting health secretary, registers 3-6% in 11 of the 18 fetched surveys, better than several names the panel priced individually, yet trades at 0.35 cents inside the bucket tier. If this board gets re-cut by volume later in the cycle, his is the contract most likely to move tiers.

How To Read These Prices

The models can tell you where they part from the crowd; the number in front of you still has to be understood in context.

A Worked Example: Rubio At 29.5 Cents

Rubio's Yes trades at 29.5 cents, which reads naively as 29.5% and converts to about +239 in American odds. Two adjustments matter. First, the whole 38-contract board's midpoints sum to 98.7 cents, so unlike a heavily vigged sportsbook futures page there is almost no overround to strip: his de-vigged share is about 29.9%. Second, the panel's 15.5% blend, translated the same way, would price the identical contract near +545. The distance between +239 and +545 is what a 14-point probability disagreement feels like in a bettor's units, and it is the entire thesis of this board in one line. The full cents-to-odds mechanics are in our sportsbook-to-Kalshi translation guide.

Then the honesty a sportsbook line never forces on you. This market's clock runs until the party nominates someone and they accept, as much as two years away, with a listed expiration 27 months out: capital in a position here is locked while spreads on the sub-cent names run nearly as wide as the prices themselves, and Kalshi's trading fees apply on the way in. Line movement between now and the convention, not settlement, is how most positions on a board like this actually resolve. For readers who price the daily slate rather than 2028, our live odds screen and free expert picks do the same compare-the-number work across sportsbooks that this page does across a probability panel. And if exchange mechanics are new to you, Kalshi's politics markets for sports bettors covers the translation.

When This Board Re-Scores

This page's numbers are a snapshot of the quiet window: 27 months from the listed expiration, with the fetched polling feed ending June 14 and no declared candidates in any structured source. The card's own coverage warnings are the re-score calendar. The November 2026 midterms will settle two facts the panel repeatedly flagged as gating events, Ramaswamy's Ohio race and the broader environment read, and the first declared-candidacy wave will convert name-identification polling into something the models say they would weight differently.

Want the re-scored board when it moves? The panel re-runs this market after the November 2026 midterms and again when the first major candidacies are declared, on this same page. The email signup at the end of this article gets each re-score first, wherever you are reading from.

The Bottom Line

The market and the panel agree this is J.D. Vance's race to lose and disagree about who is actually second. Kalshi's crowd prices Rubio as a near-co-favorite at 29.5 cents; eight price-blind models, four of which then defended the number against their peers, say the polling underneath that price is conditional support worth about half as much, and they hand the difference to Trump Jr., the buckets, and the field. The panel's own graded record says the crowd wins arguments like this slightly more often than not, which is the right spirit to carry into a market with 27 months left on the clock. The same panel prices the other side of the aisle in the 2028 Democratic nominee odds board, rolls both nominations into the general in the 2028 presidential election odds board, and scored the nearer-term cycle in the 2026 midterms balance-of-power verdict.

To be explicit about what this page is: an analytical comparison of one crowd's prices and one panel's estimates, on a CFTC-regulated exchange available to adults 18+ in eligible states as of August 2026. It is not advocacy for any candidate or party, and none of it is advice about what anyone should trade or how anyone should vote. The panel's numbers will be graded against settlement in 2028, the same way every board it prices is graded.

Hottest Prediction Markets Right Now

• 2028 Democratic presidential nominee · $166M traded
• Rocket Classic Winner · $85M traded
• 2027 Pro Football Champion · $52M traded
• Pro Baseball Champion · $41M traded
• Bitcoin price at the end of 2026 · $30M traded
• 2027 Pro Basketball Champion · $19M traded

Every market above links to our full AI model verdict; browse them all on the OddsShopper prediction markets hub.

Verdicts generated August 1, 2026, in two rounds (independent, then revision). Prices as of August 1, 2026. Panel: ChatGPT GPT-5.5, Claude Fable, Claude Opus, Claude Sonnet, Gemini 3.1 Pro, GLM 5.2, Kimi K3, DeepSeek V4, all price-blind. These are model estimates, not predictions of fact and not financial advice.