Next Supreme Court Justice Odds: The Model Verdict Vs. Kalshi's Board
Kalshi turned one of the biggest questions in American politics into a 39-name market: who will be the next person confirmed to the Supreme Court? The crowd has favorites, with two federal appeals-court judges on top and a long bench of Trump-era names behind them. We handed five AI models the same fetched facts, hid every market price from them, and asked each to price the whole field plus the odds that Justice Samuel Alito or Justice Clarence Thomas actually steps down. The models agreed on something the board's prices understate: before you can name the next justice, a seat has to open, and on today's facts that is far from certain.
The Quick Answer
The board and the panel disagree about the premise, not just the pick. Kalshi lists 39 possible next justices, led by 5th Circuit judge James Ho near 18 cents and fellow 5th Circuit judge Andrew Oldham near 16 cents, and if you add up the whole board it sums to well over 100 cents, which is the crowd treating a confirmation by January 20, 2029 as likely. Our five price-blind models see it differently: they blend the chance that no new justice is confirmed in that window at about 63%, so they give the entire field only a 37% combined chance of producing anyone at all. The reason is on the record. There is no current vacancy, sources close to both Alito and Thomas said in 2026 that neither is retiring this year, and Alito has been hiring clerks for the next term. The full 39-name board, the model-by-model numbers, the Alito and Thomas retirement ladders, and the handful of dark horses the panel would not bury are all below.
Get the panel's verdict when this market settles. We grade every Model Verdict call in public once the market closes, and we re-score this board the moment a real retirement or nomination breaks. Grab the settlement recap and the next re-scored board through our email list at the end of this article, no charge.
The one-look read: The board prices a new justice as the base case; the five-model panel says the base case is that both aging justices stay, blending a 63% chance nobody new is confirmed by 2029. Where the crowd sees favorites, the machines see a seat that may never open in the window.
New to Kalshi event markets? Start with our plain-English guide to how prediction markets work for how a cent price becomes a probability and how these contracts settle.
The Market
| Venue | Kalshi, a CFTC-regulated event-contract exchange (18+; availability varies by state, as of August 2026) |
| The Event | "Who will be the next Supreme Court justice?" sold as 39 mutually-exclusive yes/no contracts, one per candidate |
| The Contract | Per Kalshi's settlement rules, a candidate resolves YES only if that person is the first individual confirmed by the Senate to a Justice seat by January 20, 2029. A seat must open and a nominee be confirmed. If no one is confirmed by that date, every candidate resolves NO |
| Settles | On the first confirmation, otherwise the board expires around January 20, 2029 |
| Prices Below As Of | August 3, 2026, drawn from recent daily closes on a thin, long-dated book, so treat single-cent moves as noise. Prices on this page refresh during any retirement or nomination news wave |
The Setup: You Need A Vacancy First
Most "who's next" markets start with a job that is already open. This one does not. There is no Supreme Court vacancy today, so every name on the board is a bet on two things happening in order: a seat opens through retirement or death, and the Senate confirms a replacement before January 20, 2029. Our models received the following as verified, dated facts, and nothing about the prices:
- The Court Has No Opening, And A Conservative 6-3 Majority. The nine sitting justices range from Amy Coney Barrett, 54, to Clarence Thomas, 77. The two oldest, Thomas (77) and Alito (76), are the names driving every retirement rumor because they are the seats most likely to turn over while a Republican president and Senate could fill them.
- Both Aging Justices Signaled They Are Staying, At Least For Now. Sources close to Alito and Thomas told CBS News and ABC News in 2026 that neither is planning to retire this year, and Alito has been hiring law clerks for the next term, a conventional signal that a justice intends to keep serving.
- The Rumor Cycle Is Loud, And Sometimes Wrong. In June 2026, NPR published and then retracted a report that Alito was retiring. No retirement was announced. President Trump has publicly urged both to step down so he can name younger successors, and Senate Majority Leader John Thune has said Republicans would be prepared to confirm a replacement.
- The Confirmation Math Currently Favors A Fast Replacement. Republicans hold the Senate 53 to 47, and since 2017 a Supreme Court confirmation needs only a simple majority, so a nominee could be seated without any Democratic votes. That window is not certain to last: the November 2026 midterms could flip control, and Democrats need a net of four seats to do it.
- History Says Justices Time Their Exits. The last ten justices to retire were about 80 on average, and the last seven left while the party aligned with them controlled both the White House and the Senate, so a like-minded successor could be confirmed. Thomas reaches that average retirement age inside this window; Alito does not.
The models weighed all of that and landed in the same place five different ways: a seat opening and a confirmation completing by early 2029 is a coin flip at best, and more likely does not happen. As our Fable seat put it after the revision round, the stay signals "only cover 2026," while "the aligned-government retirement incentive persists," and "combined mortality risk for two justices aged 76-77 over 2.5 years is roughly 15%." That is why the panel spends most of its probability on the outcome the board has no clean contract for: nobody new.
The Board
The mobile-friendly view. These are the panel's post-revision blends against the market's cent prices. Every listed name still requires a seat to open first.
| Outcome | Role | Market | AI blend |
|---|---|---|---|
| James Ho | Judge, 5th Cir. | 18C | 4% |
| Andrew Oldham | Judge, 5th Cir. | 16C | 2% |
| Amul Thapar | Judge, 6th Cir. | 10C | 3% |
| Aileen Cannon | Judge, S.D. Fla. | 10C | 3% |
| D. John Sauer | U.S. Solicitor General | 9C | 2% |
| Steven Menashi | Judge, 2d Cir. | 8C | <1% |
| Emil Bove | Judge, 3d Cir. | 6C | 2% |
| Ron DeSantis | Governor, FL | 6C | <1% |
| Michael Park / Kenneth Lee | Judges, 2d / 9th Cir. | 5C | <1% |
| 29 More Candidates | Each priced ≤4c on a thin book | ≤4C | ≤2% each |
| No New Justice Confirmed By 2029 | Both aging seats hold | No Contract | 63% |
The single most important row is the last one. There is no "nobody" contract to buy on Kalshi, but it is where the panel puts most of its weight, and it is the honest headline of this board.
Every Seat's Number: All 39 Candidates
Every model priced the full field price-blind, and each column is a proper distribution: the candidate numbers plus a "no confirmation" bucket and an "unlisted person" bucket sum to about 100 per model. These are the post-revision (round two) figures, sorted by the blended estimate. A dash means that seat rounded the candidate to zero.
| Outcome | Role | Market | Fable | Opus | Sonnet | GLM | DeepSeek | Blend |
|---|---|---|---|---|---|---|---|---|
| James Ho | Judge, 5th Cir. | 18C | 8 | 5 | 5 | 2 | 2 | 4% |
| Aileen Cannon | Judge, S.D. Fla. | 10C | 4 | 3 | 3 | 1 | 2 | 3% |
| Amul Thapar | Judge, 6th Cir. | 10C | 3 | 3 | 3 | 2 | 2 | 3% |
| Andrew Oldham | Judge, 5th Cir. | 16C | 5 | 2 | 3 | 1 | 2 | 2% |
| Emil Bove | Judge, 3d Cir. | 6C | 4 | 2 | 2 | 1 | <1 | 2% |
| D. John Sauer | U.S. Solicitor General | 9C | 3 | 2 | 2 | 2 | 2 | 2% |
| Neomi Rao | Judge, D.C. Cir. | 2C | 2 | 2 | 2 | 2 | 2 | 2% |
| Barbara Lagoa | Judge, 11th Cir. | 2C | 2 | 2 | 2 | 2 | 1 | 2% |
| Kathryn Mizelle | Judge, M.D. Fla. | <1C | 2 | 1 | 1 | <1 | <1 | 1% |
| Lawrence VanDyke | Judge, 9th Cir. | 3C | 2 | 1 | 1 | <1 | <1 | 1% |
| Kevin Newsom | Judge, 11th Cir. | <1C | <1 | 1 | 2 | <1 | <1 | 1% |
| Steven Menashi | Judge, 2d Cir. | 8C | 1 | <1 | <1 | <1 | <1 | <1% |
| Kate Comerford Todd | Fmr. WH counsel | <1C | <1 | <1 | <1 | 2 | <1 | <1% |
| Patrick Bumatay | Judge, 9th Cir. | 4C | 2 | <1 | <1 | <1 | <1 | <1% |
| Stuart Kyle Duncan | Judge, 5th Cir. | <1C | <1 | <1 | <1 | <1 | <1 | <1% |
| Allison Jones Rushing | Judge, 4th Cir. | <1C | <1 | <1 | <1 | <1 | <1 | <1% |
| Michael Park | Judge, 2d Cir. | 5C | <1 | <1 | <1 | <1 | <1 | <1% |
| Kenneth Lee | Judge, 9th Cir. | 5C | <1 | <1 | <1 | <1 | <1 | <1% |
| Joan Larsen | Judge, 6th Cir. | <1C | <1 | 1 | <1 | <1 | <1 | <1% |
| Britt Grant | Judge, 11th Cir. | <1C | <1 | <1 | <1 | <1 | <1 | <1% |
| Stephanos Bibas | Judge, 3d Cir. | <1C | <1 | <1 | <1 | <1 | <1 | <1% |
| Gregory G. Katsas | Judge, D.C. Cir. | <1C | <1 | <1 | <1 | <1 | <1 | <1% |
| David Stras | Judge, 8th Cir. | <1C | <1 | <1 | <1 | <1 | <1 | <1% |
| Trevor McFadden | Judge, D.D.C. | <1C | <1 | <1 | <1 | <1 | <1 | <1% |
| Evan Young | Justice, TX Supreme Court | <1C | <1 | <1 | <1 | <1 | <1 | <1% |
| Mike Lee | U.S. Senator, UT | 2C | <1 | <1 | <1 | <1 | <1 | <1% |
| Allison Eid | Judge, 10th Cir. | <1C | <1 | <1 | <1 | <1 | <1 | <1% |
| Ted Cruz | U.S. Senator, TX | 2C | <1 | <1 | <1 | <1 | <1 | <1% |
| Yaakov Roth | DOJ / private bar | 1C | <1 | <1 | <1 | <1 | <1 | <1% |
| Matthew Kacsmaryk | Judge, N.D. Tex. | <1C | <1 | <1 | <1 | <1 | <1 | <1% |
| Ron DeSantis | Governor, FL | 6C | <1 | <1 | <1 | <1 | <1 | <1% |
| Kevin Brobson | Justice, PA Supreme Court | <1C | <1 | <1 | <1 | <1 | <1 | <1% |
| Tom Cotton | U.S. Senator, AR | <1C | <1 | <1 | <1 | <1 | <1 | <1% |
| Anna St. John | Attorney | 2C | <1 | <1 | <1 | <1 | <1 | <1% |
| Kristen Waggoner | ADF general counsel | <1C | <1 | <1 | <1 | <1 | <1 | <1% |
| Mark Martin | Fmr. NC chief justice | <1C | <1 | <1 | <1 | <1 | <1 | <1% |
| Patrick Wyrick | Judge, W.D. Okla. | <1C | <1 | <1 | <1 | <1 | <1 | <1% |
| Clint Bolick | Justice, AZ Supreme Court | <1C | <1 | <1 | <1 | <1 | <1 | <1% |
| Morse Tan | Law dean | <1C | <1 | <1 | <1 | <1 | <1 | <1% |
| No New Justice Confirmed By 2029 | Both seats hold | No Contract | 48 | 64 | 58 | 68 | 75 | 63% |
These are model estimates, not predictions of fact and not financial advice. The models were scored without seeing any market prices, they are graded against real settlements, and they are wrong regularly. Event contracts are for adults 18 and older where legal, on a CFTC-regulated exchange.
Every number in this piece gets graded in public once the market settles. You can see how this lane has done on past calls on the full graded scoreboard, which is our standing record of hits and misses.
A disclosure on the panel. Our standard Model Verdict panel runs eight seats. Three were unavailable on this machine when these verdicts were generated: the Kimi seat (a provider error), the ChatGPT seat (an expired login), and the Gemini seat (the tool was not installed). So this article runs on five models, Claude Fable, Claude Opus, Claude Sonnet, GLM, and DeepSeek, each of which returned a complete field distribution and all three retirement ladders. All five scored price-blind on August 3, 2026, then read one another's anonymized reasoning in a revision round.
The Big Finding: The Panel Thinks The Seat May Not Open
The board's prices only make sense if a confirmation is likely, and that is exactly the assumption the panel pushed back on. All five models put more weight on "no new justice by 2029" than on the entire field of candidates combined. After the revision round the individual "no confirmation" numbers ran from 48% (Fable, the most aggressive) up to 75% (DeepSeek, the most skeptical), blending to about 63%.
That spread is the real disagreement on this page, and it is an honest one. The bullish-on-a-vacancy case, made best by Fable, is that the stay signals only cover 2026, the strategic incentive to retire under an aligned government is live through 2028, Thomas reaches the historical average retirement age of 80 inside the window, and two justices in their late seventies carry real actuarial risk over two and a half years. The skeptical case, made by DeepSeek, is blunter: "Alito is hiring clerks into 2027, both he and Thomas signaled no 2026 retirement, and the historical average retirement age is 80. With no vacancy announced and explicit disavowals, a 75% chance of no confirmation by Jan 2029 remains well-calibrated." Opus split the difference, nudging its number up after reading the others but stopping short of the skeptics, noting the window still "runs to Jan 2029 with Trump pressure and an eager GOP."
Put simply: the crowd is pricing who gets the seat, and the panel is reminding everyone the seat has to come open first.
Justice Alito's Retirement Watch
Alito, 76, is the second-oldest justice and the center of most 2026 retirement chatter. Kalshi runs two separate ladders on him, and they are the cleanest place to see the panel-versus-market gap, because here the models and the crowd are pricing the exact same contracts.
| Will Alito Be Out By... | Market | Fable | Opus | Sonnet | GLM | DeepSeek | Blend |
|---|---|---|---|---|---|---|---|
| Before Sep 1, 2026 | 3C | 1 | 1 | 1 | 1 | 1 | 1% |
| Before Jan 1, 2027 | 13C | 3 | 3 | 3 | 3 | 2 | 3% |
| Before Jul 1, 2027 | 41C | 14 | 9 | 12 | 14 | 10 | 12% |
Model estimates, not predictions of fact and not financial advice. Per Kalshi's rules, each rung resolves YES if Alito retires before the listed date.
The panel sits far below the market on the mid-2027 rung, blending 12% against a 41-cent price. The models are not dismissing a retirement, they are timing it. As Opus wrote, the higher market numbers "over-weight Trump's public pressure; clerk-hiring points to serving into 2027." Every seat kept meaningful weight on the June 2027 end-of-term window, the canonical moment justices announce, while a GOP Senate is likely still in place, which is why the last rung is the only one carrying real probability. Kalshi also runs a second, near-identical Alito ladder (the "announce retirement" series), and it prices the same July 2027 outcome around 30 cents rather than 41, a gap between two contracts on essentially the same event that the panel treats as one number near 15%.
Justice Clarence Thomas's Retirement Watch
Thomas, 77, is the oldest justice, and his ladder is the one place the panel comes close to agreeing with the market on the long horizon.
| Will Thomas Be Out By... | Market | Fable | Opus | Sonnet | GLM | DeepSeek | Blend |
|---|---|---|---|---|---|---|---|
| Before Jan 1, 2027 | 9C | 4 | 4 | 5 | 6 | 5 | 5% |
| Before Jul 1, 2027 | 16C | 18 | 12 | 15 | 18 | 15 | 16% |
| Before Jan 1, 2028 | 25C | 28 | 20 | 26 | 28 | 25 | 25% |
Model estimates, not predictions of fact and not financial advice. Per Kalshi's rules, each rung resolves YES if Thomas retires before the listed date.
By January 2028 the panel blends 25%, right on top of the market's 25-cent price, and its mid-2027 number of 16% matches the board almost exactly. Age is doing the work: Thomas is the one justice who reaches the historical average retirement age inside the window, so the models give his longer-dated exit the most weight of anyone on the court. On the near date they stay below the market, anchored to the same 2026 sourcing that says he is not going this year. As Sonnet framed it, the later rungs stay "near consensus median since GOP has confirmation votes ready and historical retirement age is still 3-plus years off," while the explicit denial keeps the first rung low.
The Panel's Dark Horses
A field this deep hides a few names where at least one model saw more than the crowd did, or landed right on top of it. These are all still long shots, and the point is the split from the market, in either direction.
- Kevin Newsom (Blend About 1%, Market Under 1 Cent). The 11th Circuit judge is essentially untraded on Kalshi, yet Sonnet gave him 2% and singled him out as a credible, confirmable pick if a seat opens. When a model rates a name several times its market price, that is the panel saying the crowd has not gotten around to pricing him.
- Kathryn Mizelle (Blend About 1%, Market Under 1 Cent). A young Middle District of Florida judge with almost no market, lifted by Fable to 2%. Youth is the whole case: a nominee in her thirties or forties is precisely the "young conservative successor" the retirement pressure is built around.
- Neomi Rao And Barbara Lagoa (Blend About 2% Each). Both the D.C. and 11th Circuit judges land right on top of their 2-cent prices across every seat, the rare candidates where the panel and market simply agree. Lagoa in particular draws notice as a Florida appellate judge on every recent shortlist.
- Lawrence VanDyke (Blend About 1%, Market 3 Cents). The 9th Circuit judge is one of the deeper-bench names the crowd priced a touch higher than the panel did, a reminder the split runs both ways on a thin board.
None of these is a call to act. It is the panel flagging that on a board where the crowd has crowned two 5th Circuit judges, the machines think the deep bench is closer to the leaders than the prices imply, precisely because no one has a real edge until a seat opens.
Where The Panel And The Board Split
Two honest splits are worth naming before anyone reads these numbers as gospel.
- The premise gap. The board's cent prices sum to well over 100, which only makes sense if a confirmation is close to certain. The panel's 63% "no confirmation" blend says the opposite: the base case is that both aging justices stay through the window. That is a real disagreement about whether the event even happens, not just about who wins it. If a retirement is announced tomorrow, the entire top of this board reprices in minutes, and so would the panel.
- The two-Alito puzzle. Kalshi lists two Alito ladders that settle on materially the same event, and they trade several cents apart on the mid-2027 rung (roughly 41 versus 30). On a thin, long-dated book, that kind of gap is usually a liquidity artifact rather than a signal, and it is a good reminder to read Kalshi's written rules for the exact contract before treating any single price as the truth.
How To Read A Field Board Like This
A market like this rewards a few habits, whoever you are:
- A price is a probability, not a payout quote. A contract that pays $1 if it hits trades near the market's estimate of the odds, so an 18-cent price on James Ho is the crowd pricing that outcome around 18%, not an 18-to-1 line.
- The pennies over-round, and a "no vacancy" outcome has no ticker. Add up all 39 quoted prices and the total sits well above 100 cents, partly because there is no contract to price the most likely outcome of all, that nobody new is confirmed. When a board cannot price its own base case, the visible favorites look stronger than they are.
- Thin, long-dated markets drift. Almost nothing here trades daily, so a posted number can be stale or a single trader's view. Our guide to Kalshi liquidity and reading a thin book covers where that bites.
- Settlement is the whole game. This board resolves on the first Senate confirmation by January 20, 2029, per Kalshi's rules, which are always the governing document. For the mechanics of turning a cent price into a probability, our explainer on how prediction markets work walks through it, and our state-by-state legality guide has the current availability picture.
FAQ
Who Is The Favorite To Be The Next Supreme Court Justice On Kalshi?
As of August 3, 2026, Kalshi's board makes James Ho, a judge on the 5th Circuit, the nominal favorite around 18 cents, with fellow appeals-court judge Andrew Oldham near 16 cents and Amul Thapar and Aileen Cannon around 10 cents. Because the board settles on the first person confirmed to the Court by January 20, 2029, every one of these names first requires a seat to actually open, which is why no candidate trades as a true favorite.
Do The AI Models Think A New Justice Will Be Confirmed By 2029?
More often than not, the panel thinks the answer is no. Five price-blind models blend the chance that no new justice is confirmed by January 20, 2029 at about 63%, which leaves roughly a 37% combined chance that anyone at all is confirmed in that window. The models lean that way because there is no current vacancy, and sources close to both Justice Alito and Justice Thomas said in 2026 that neither is retiring this year.
What Are The Odds Justice Alito Retires?
Kalshi prices a retirement by mid-2027 in the 30-to-41-cent range depending on the contract, while the five-model panel blends it far lower, around 12 to 16 percent. The models weight Alito hiring law clerks for the next term and the 2026 sourcing that he is not retiring this year. Every number is a model estimate, not a prediction of fact, and the market can move on a single announcement.
What Are The Odds Justice Clarence Thomas Retires?
On Kalshi, a Thomas retirement runs about 9 cents by January 2027, 16 cents by mid-2027, and 25 cents by January 2028. The panel lands close to the market on the longest horizon, blending about 25% by January 2028, but below it on the nearer dates. Thomas, 77, is the Court's oldest member, which keeps his longer-dated odds the highest of the retirement watch.
How Were These Estimates Generated?
Five AI models each priced all 39 contracts plus the three retirement ladders without seeing any market prices, reasoning from a dated card of verified, fetched facts about the Court's composition, the confirmation math, and 2026 retirement reporting. Each then read the others' anonymized reasoning and could revise. The blend is the equal-weight average across the five. The Kimi, ChatGPT, and Gemini seats were unavailable this run and are disclosed above.
The Bottom Line
The crowd and the machines are reading the same board and arguing about the first sentence of it. Kalshi prices a new Supreme Court justice as the likely outcome by 2029 and hands the lead to two 5th Circuit judges. Five price-blind models look at the same fetched facts, a court with no vacancy, two aging justices who said they are staying, and one of them hiring clerks into 2027, and blend a 63% chance that nobody new is confirmed at all. On the retirement ladders the panel sits well under the market on Alito and roughly even on Thomas, whose age gives his exit the most weight. To be explicit, none of this is financial advice or a prediction of fact, it is where five model estimates and a real, CFTC-regulated market land today, and a single retirement announcement would rewrite the whole page. Every number here gets graded in public once the market settles.
Hottest Prediction Markets Right Now
- 2028 Democratic presidential nominee · $166M traded
- Rocket Classic Winner · $124M traded
- 2027 Pro Football Champion · $51M traded
- Pro Baseball Champion · $40M 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, and see how every settled call actually scored on the full graded scoreboard.
