The U S Treasury Department has the the authority to cut a bank loose from the from the U S financial system as a result of the Patriot Act passed after 9 11 Actually I think they always had the authority but implementation used to be more complicated This is what has happened to BDA IMO it s only natural that the U S Treasury exercises authority over U S dollar accounts where ever they might be located Otherwise any overseas bank could just create U S dollar accounts out of funny money deposits I know that China regulations concerning yuan accounts overseas so its not only the U S that does this The counterfeit North Korean notes used to be called superbills but there is now readily available technology to detect them If BDA was fooled it s because they didn t want to know