As far as I can tell, "keeping the Euro" would simply involve for the country to declare the Euro legal tender. Even if the EU wanted to prevent that, it's not

As far as I can tell, "keeping the Euro" would simply involve for the country to declare the Euro legal tender. Even if the EU wanted to prevent that, it's not clear to me how it would. That does not mean that the country would have a say in Euro governance (controlling the mount of Euro "printed"), but the ECB is fairly independent anyway. According to this list, several smaller non-EU countries are using the Euro already (and several countries worldwide are using the Dollar, including Zimbabwe—pretty sure they don't get invites to FOMC meetings): https://qz.com/260980/meet-the-countries-that-dont-use-their-own-currency/ https://qz.com/260980/meet-the-countries-that-dont-use-their...