There is a vid floating around on the Internet of one of the Assistant United States Attorneys testifying before Congress. I'll try to find it. I did find the following paragraph from Poker News:

Annie Duke, Others Testify at House Judiciary Hearing on Online Gambling | Poker News



Catherine Hanaway, U.S. District Attorney for eastern Missouri, spoke on behalf of the Department of Justice. While Hanaway started her testimony with the Department's position that current laws deem all forms of internet gambling to be illegal, follow-up testimony during the question and answer period found some caveats beneath the DOJ's veneer. For instance she acknowledged that it was not illegal for US residents to gamble online; it was only illegal for companies to provide online gambling services to US residents. She also admitted that there were no laws that specified that online gambling, with the exception of sports betting, was illegal but that the DOJ felt "they were covered." All the legal prosecutions that Hanaway cited during her testimony were sports book related. Conyers pressed on the obvious inconsistencies with the horse racing carve out, asking why she didn't cite any legal action against online horse racing. She stated that she was only mentioning larger legal cases, but couldn't come up with anything related to the online horse racing industry.