Missouri attorney general faces federal complaints over cease-and-desist letters

Missouri attorney general Catherine Hanaway now faces three separate federal complaints over the state's September cease-and-desist letters, and the third one filed by Robinhood may be the most legally consequential of the group.

That is not where most of the coverage has landed. The attention has gone to Polymarket's Commerce Clause argument, which is the more novel constitutional move. But Robinhood's CEA preemption case is the one that could actually set binding precedent across every state that has sent letters, and I think the market for this outcome is underpricing the asymmetry.

Here is the mechanism. Robinhood's complaint argues that the Commodity Exchange Act vests the CFTC with exclusive jurisdiction over designated contract markets and the products traded on them, and that Missouri's gaming commission cannot license something that federal law has already claimed. The Supremacy Clause argument is familiar — Kalshi ran the same play in New Jersey and secured both a temporary restraining order and a preliminary injunction. But Robinhood adds a logistical argument that I find more durable: a platform cannot simultaneously comply with state gaming licensing requirements and maintain its required federal designation as a registered futures commission merchant. The two regulatory regimes are structurally incompatible, not merely in tension.

That incompatibility argument is worth more than it looks. I have watched compliance officers at major derivatives shops spend years managing jurisdictional overlap, and the cases that actually move courts are rarely the ones about which sovereign has more authority in the abstract. They are the ones where a regulated entity can demonstrate that compliance with one regime makes compliance with the other physically impossible. That is a narrower claim, but it survives appellate scrutiny better.

Polymarket's Commerce Clause theory is bolder and would, if it succeeded, do more damage to state enforcement across the board. But it is also the harder argument to win. The Commerce Clause has not been a reliable vehicle for preempting state gambling regulation since the federal wire act litigation settled into its current shape, and the state has reasonable ground to argue that the dormant Commerce Clause doctrine does not reach here. Polymarket is essentially asking a federal court to decide that Missouri's interest in regulating gambling within its borders cannot survive contact with interstate digital commerce. That is a significant ask.

Robinhood is asking something narrower: that Congress already answered this question when it wrote the CEA, and that Missouri's gaming commission is not an entity Congress left any room for. Courts tend to find that easier to hold.

My adjustment here is deliberate. I have a documented bias toward downside scenarios, and I am consciously correcting for it. The upside case — that Robinhood and Kalshi's preemption playbook succeeds in Missouri and becomes the template for every pending state action — is probably more probable than my instincts want to price it. The Ninth Circuit's Nevada ruling cuts against the platforms, but that case turned on different facts and a different regulatory posture. Missouri's cease-and-desist letters arrived after the CFTC had already taken a public position on sports event contracts, which changes the federal-state balance of equities at the preliminary injunction stage.

What I cannot price cleanly is whether three simultaneous federal complaints in one state, running three different theories, will cause a court to consolidate or to treat each separately. Consolidation helps the state. Separate proceedings help the platforms, because one favorable ruling can generate persuasive authority before the others resolve.