Can't do it, individual states can't print money and freedom of movement means the free rider problem will pop up quickly.
> can't print money
But can they raise taxes?
> freedom of movement
EU also has freedom of movement, but vastly different social security systems.
Language is of course an extra barrier, but how much people will move is overrated. And maybe you could restrict supposed benefits to people who have lived there in a few years.
Obviously IANAL, but i am thinking - seems like you generally hate your government no matter who it is, so maybe states should be a bit more independent.
> But can they raise taxes?
Sure, but the math doesn't work out. Vermont and California have both tried in various forms.
> EU also has freedom of movement, blah blah blah
They also coordinated the laws between the member countries. That's exactly what the federal government would need to do in this case, very good! The EU system doesn't work particularly well either, because it's loosely confederated. The US government has far more ability to coordinate the States.