Well the worst case would be really bad. I figure we have a 3 year window before it became legal. Keep fighting back and it will increase the size of the window.
It really could go either way, the govt could come up with a simple way to tax all American gamblers, then let them be the grownups they are, and let them play at any site they want to.
I could also see the Vegas guys greasing the right people to make it as boring and regulated as the Lottery, and all through the land based giants.
Dan