In 2006 Congress passed, and President George W. Bush signed, legislation to stop the spread of Internet gambling. At the time, no one was sure whether a law could deter shady offshore operators. But by targeting the money flows and banks that facilitated these businesses, the law worked far better than most people imagined. Until now, that is. The doors to the virtual casino are reopening, this time with the gambling sites based here in the USA, thanks to a 2011 Justice Department finding that earlier bans applied only to sports betting…