From what I understood, online gambling was not illegal in any state, but it was illegal to use credit cards to cash out your winnings. This restriction was slipped into, where else, the "Safe Harbor Act of 2006."
If DC allows this I wonder how they expect people to cash out their winnings.
Almost.
The UIGEA, slipped into that safe harbor act, made it illegal for BANKS to allow DEPOSITS to online gambling websites that were ALREADY ILLEGAL. It also expressely ALLOWED WITHDRAWALS from online gambling sites in any form. As online poker wasn't illegal, it should not have been affected, and withdrawals definitely should not have been affected.
However, withdrawals and online poker sites were easy targets to pick on because no one who handled the money was going to be dumb enough to show up in a US Federal court (Is it >95% conviction rate there?); so the DOJ started seizing player withdrawals.