The DOJ’s Office of Legal Counsel’s 2019 opinion stated online casinos and online poker are banned under the UIGEA and Wire Act. Specifically, Rod Rosenstein announced interstate online gambling is banned, so any online betting that crosses state borders is banned.
Online poker with shared liquidity between states in particular was shut down, though a lawsuit by Pennsylvania, New Jersey and New Hampshire challenges the DOJ’s new position. The federal court system has not sent down a final ruling on the case yet, so the ability of the federal government to enforce the 2019 DOJ opinion is still in doubt.