Because exchanges are able to run in the USA. So I am sure there must be a path to create a legal compliant exchange.
Do you have any idea?
I guess the first question would be how do you ensure the securities being exchanged are compliant. At the very least they would have to be registered (or fall under one the exemption rules, but not many would be applicable AFAICS). IMHO, the issuers of these securities run a greater legal risk than the operator of the exchange.
Maybe something can be done in the framework of this new crowd funding legislation, but i havent read up on it yet.