I am not a crypto currency expert nor have I ever used it but I suspect they would regulate the institutions that convert that virtual currency to a countries s

I am not a crypto currency expert nor have I ever used it but I suspect they would regulate the institutions that convert that virtual currency to a countries standard currency such as exchanges. So I suppose they could not stop blockchain without some effort but they might be able to stop pulling money out of the system. A potential real world example of why this might interest the US government would be to prevent President Vladimir Putin from siphoning his $200 billion from his Oligarch's that are holding all the money for him in US financial institutions. Sanctions could be potentially side-stepped by crypto exchanges and I am sure this has crossed their mind given the recent usage of crypto in Afganistan to get money to some folks that are starving.