The Supreme Court has no say over a state choosing to ban gambling.

What is the Supremacy Clause?

The case would be on CFTC authority vs state authority.

You’d be hard pressed to argue that states should be individually able to control futures trading

I do agree that prediction markets are BS gambling pretending to be something else.

But factually, SCOTUS does have authority over the application of the supremacy clause. At some point they will send federal agents in and enforce it themselves.

Except that the Supreme Court does have a say over whether or not the Supreme Court has a say over a state choosing to ban gambling.