How would an American feel if they discovered overnight their state had left the U.S. and they were no longer American?

I suppose it would depend on whether that state was being treated fairly. Do US states pay a lot more into the US than other states. I have no idea. Do hard working US states subsidise other states. I have no idea. Do US states get dictated to by Brussels, sorry I meant Washington. I have no idea. Are US and EU the same sort of thing? I have no idea.