Mostly circumstantial evidence. Regulators/feds have taken down one of the largest and most crypto friendly bank, Silvergate. Federal Reserve Board unanimously denied Custodia to be a member of Federal Reserve System.

And the latest Economic Report of the President[1] has a full chapter (Chapter 8) in which they make their stance clear in no uncertain terms.

[1] https://www.whitehouse.gov/wp-content/uploads/2023/03/ERP-20...