Because its the law, and must be reviewed. Once its ok'd the states are finding its something they wish they'd never approved. We are still new at this and are finding out all the negatives and very few positives. Read some of the articles to find complete answers as to who it has to be approved by. When states find out what is really going on they are holding back from approvals, especially when the local citizenry stand up and say NO. Especially when they learn that they won't gain anything and have much to lose.
Indian tribes should not need any permission for foreign governments to open a casino.