For example, the third parties might offer financial bonuses to retailers who play. In addition, participants would receive a sort of tax amnesty. The states could do some legal ganging up on Amazon and Wal-Mart in the same way that they went after tobacco companies. They might have a case. But these types of questions are as yet largely unsettled, and it might be more expensive for dot-com companies to litigate than to go with the program.
Critics argue that the governors' proposed tactics are too strong-armed.
If the answer to either of those questions is no, then the NGA plan falls apart. Besides, the states may have trouble getting merchants to play, despite the incentives. There need to be some rules of the game for states to collect use taxes. But if the result is replacing the current inconsistent patchwork of taxes with another, it wouldn't much satisfy anyone. It will make it that much harder to go back and change this later.