Enforcing it is trivial for a sovereign nation that issues it's own currency and collects taxes in that currency. Just as we've seen; they can regulate the on/

Enforcing it is trivial for a sovereign nation that issues it's own currency and collects taxes in that currency. Just as we've seen; they can regulate the on/off ramps between local currency and crypto. If you've got a method to turn meaningful amounts of BTC into USD without being subject to KYC regulations; then the US government is probably already building a federal money laundering case against it.