Has Idaho taken any action against Kalshi or Polymarket?

No. As of 1 September 2026 there is no cease-and-desist letter, lawsuit, criminal charge or announced investigation from any Idaho authority on the public record.

Does the 28 August Ninth Circuit ruling apply in Idaho?

Yes. Idaho is one of the nine states in the Ninth Circuit, so the ruling is binding precedent there. But a decision that a state may enforce its gambling laws is permission, not a command. Somebody in Idaho still has to act on it.

Could Idaho ban prediction markets by passing a law?

It would not need to add a prohibition so much as enforce the one it has. The harder problem runs the other way: because the ban sits in the constitution rather than in statute, legalising event contracts in Idaho would require a constitutional amendment, not a bill.

Is Kalshi legal in Idaho?

Explainer · Updated September 1, 2026 · 18+ · Not legal advice · By BetG8 Editorial · Prediction Markets

Idaho is the only state in the Ninth Circuit without a prediction market page on this site, and until last week that was because there was nothing to write. That changed on 28 August 2026, and it changed in an unusual way: the ruling that gave Idaho the power to act was a ruling Idaho helped win, in a case Idaho was not a party to. Five days later the state has done nothing with it.

Short answer: Kalshi and Polymarket are both reachable from Idaho today, and there is no geofence. Idaho has issued no cease-and-desist, filed no lawsuit and opened no public investigation. That is not because Idaho law permits event contracts — the state constitution prohibits gambling outright and the criminal code is written broadly enough to reach them. It is because nobody in Idaho has filed anything.

Status at a glance

Question	Answer
Is Kalshi available in Idaho?	Yes. No geofence.
Is Polymarket available?	Yes.
State enforcement action on record	None. No letter, no suit, no investigation announced.
Legal sportsbook in Idaho	No.
Paid daily fantasy	No. Operators withdrew after a 2016 agreement with the attorney general.
Governing law	Idaho Constitution art. III, § 20; Idaho Code §§ 18-3801 to 18-3802.
Federal circuit	Ninth Circuit — Kalshi lost 3-0 there on 28 August 2026.
Idaho’s role in that case	Co-signed the 39-state brief backing Nevada, 23 March 2026.

What Idaho law actually says

Most states prohibit gambling by statute, which means a legislature can carve out an exception whenever it wants to. Idaho put the prohibition in its constitution. Article III, section 20 declares gambling contrary to public policy and strictly prohibited, and then lists the only things allowed: a state lottery, pari-mutuel wagering on horse races, and charitable bingo and raffles. Everything outside that list is barred at the constitutional level, and adding to the list requires a constitutional amendment rather than a bill.

The criminal definition sits in Idaho Code section 18-3801, and it is worth reading closely if you care about event contracts. Idaho defines gambling as risking money or other value for gain, contingent in whole or in part upon lot, chance, or the operation of a gambling device — or upon a future contingent event not under the person’s control or influence. That last clause is not standard language. Most state codes turn on whether a game is one of chance or skill, which is the argument prediction markets are built to win. Idaho’s clause turns on whether the outcome is outside your control, which is a description of an event contract rather than a defence against being one. Section 18-3802 makes participation a misdemeanour.

Idaho signed the brief that won

On 23 March 2026 Attorney General Raúl Labrador joined a 39-state coalition filing an amicus brief in the Ninth Circuit in support of Nevada. The brief made four arguments: that a federal agency’s jurisdiction has limits, that displacing an area of traditional state authority requires clear authorisation from Congress rather than inference, that state police powers survive federal registration schemes, and that the Commodity Futures Trading Commission has no expertise in gambling regulation and has never claimed any.

Labrador’s own framing named his state directly. States like Idaho that choose to ban sports betting, he said, would be prevented from enforcing those bans under the CFTC’s theory — an unelected federal agency claiming it had discovered hidden authority in fifteen-year-old financial reform laws to override state gambling laws nationwide. Congress, he said, never granted that power.

That is a clear statement of intent from March. It is the reason the silence since 28 August is worth logging rather than assuming.

What 28 August changed

A three-judge panel of the Ninth Circuit ruled 3-0 in No. 25-7516 that the Commodity Exchange Act does not preempt Nevada’s gaming laws as applied to Kalshi’s sports event contracts. Judge Ryan D. Nelson wrote, joined by Bridget S. Bade and Kenneth K. Lee. The panel accepted that federal law preempts state law for swaps traded on a designated contract market, then held that sports event contracts are not swaps — Congress used the words event and occurrence as distinct terms, and a reading wide enough to swallow a table tennis match lacks a limiting principle. The panel added that CFTC Rule 40.11(a), which bars gaming contracts on a designated contract market, remains in force.

The Ninth Circuit covers Alaska, Arizona, California, Hawaii, Idaho, Montana, Nevada, Oregon and Washington. Inside those nine states this is now binding law, not persuasive authority. The practical difference for Idaho is large. Before 28 August, an Idaho enforcement action would have had to win the preemption argument from a standing start, against a federal regulator that had already filed briefs on the other side. After 28 August, that argument is settled in Idaho’s own circuit and an Idaho action starts from the question of whether Kalshi’s contracts fit section 18-3801 — a question of state law, decided by state courts.

Two of the nine states have already converted the ruling into something operational. Nevada has a court-supervised geofence that went live on 12 August, and Washington is under a King County order with a comprehensive geofence deadline of 2 September carrying a penalty of $120,000 a day. Idaho has neither, because Idaho has not asked for either.

Why nothing has happened

The straightforward explanation is institutional rather than legal. Nevada has a Gaming Control Board with investigators, a budget and a statutory mandate to police unlicensed wagering; it sent people to place trades from inside the state to test compliance. Idaho has no equivalent body. The lottery is run by the state lottery commission, pari-mutuel racing has its own regulator, and everything else falls to the attorney general and to county prosecutors under the criminal code. Nobody in that structure wakes up owning the question of who is operating an unlicensed market online.

The second explanation is that Idaho has no money in the outcome. The usual account of why states fight prediction markets is that they are protecting licensing fees and betting tax. Idaho collects neither, because Idaho has no sportsbook to license and no handle to tax. Whatever Idaho does here, it does for the principle, and principle moves slower than revenue.

That said, the comparison that undercuts both explanations is Utah. Utah has no sportsbook, no commercial casino and no betting tax either, and Utah nevertheless took Kalshi to final judgment and won on 4 August 2026 — the first and still the only final judgment on the merits any state has obtained. The difference between Utah and Idaho is not the statute and it is not the incentive. It is that someone in Utah filed.

What would have to happen next

There are five routes from where Idaho is now to a state where Kalshi is geofenced, and they run at very different speeds.

Path	Who acts	How fast
Cease-and-desist letter	Attorney general’s office	Days. Tennessee and Connecticut both started here.
Civil suit for an injunction	Attorney general’s office	Months. This is the Nevada and Utah route.
Criminal charge under § 18-3802	County prosecutor	Months, and a misdemeanour at the end of it.
A statute or ballot measure	Idaho Legislature, which convenes in January	Next session at the earliest.
Federal resolution	US Supreme Court	New Jersey’s cert petition in Flaherty is due 3 September 2026.

What to watch

Two dates sit immediately ahead. Washington’s comprehensive geofence is due on 2 September with $120,000 a day attached, which will be the first hard test of whether a Ninth Circuit state can make an order stick in practice rather than on paper. New Jersey’s deadline to petition the Supreme Court in the Third Circuit case is 3 September; because the Ninth Circuit reasoning contradicts the Third Circuit head-on rather than distinguishing it, that petition now arrives with an acknowledged split behind it.

For Idaho specifically, the thing to watch is much smaller and much less dramatic: whether the attorney general’s office says anything at all. A single letter would move Idaho from the no-action column to the enforcement column overnight, and it would cost the state almost nothing to send. Five days of silence is not yet a decision. Thirty would be.

We track every dated move in this dispute, state by state, on our prediction market change log, and current status for all fifty states on the Kalshi legality tracker. If Idaho acts, it will appear there the same week.

FAQ

Is Kalshi legal in Idaho?: Kalshi operates in Idaho and there is no geofence, but that is not the same as being lawful. Idaho’s constitution prohibits gambling outside a short list of exceptions that does not include event contracts, and the state criminal definition reaches wagers on a future contingent event outside the participant’s control. No Idaho authority has tested that against Kalshi, so the question is unresolved rather than settled in Kalshi’s favour.
Has Idaho taken any action against Kalshi or Polymarket?: No. As of 1 September 2026 there is no cease-and-desist letter, lawsuit, criminal charge or announced investigation from any Idaho authority on the public record.
Does the 28 August Ninth Circuit ruling apply in Idaho?: Yes. Idaho is one of the nine states in the Ninth Circuit, so the ruling is binding precedent there. But a decision that a state may enforce its gambling laws is permission, not a command. Somebody in Idaho still has to act on it.
Is sports betting legal in Idaho?: No. Idaho has no legal sportsbook, retail or online. Article III, section 20 of the state constitution allows only the state lottery, pari-mutuel wagering on horse races, and charitable bingo and raffles. Paid daily fantasy operators also left Idaho after a 2016 agreement with the attorney general.
Could Idaho ban prediction markets by passing a law?: It would not need to add a prohibition so much as enforce the one it has. The harder problem runs the other way: because the ban sits in the constitution rather than in statute, legalising event contracts in Idaho would require a constitutional amendment, not a bill.