this whole saga has been really interesting. Amazon has always taken the position that unless it has a bricks & mortar presence (warehouse) in a state it doesn't have to collect sales tax. As it has grown, it now has bricks in many states, and Bezos has stated that they want to get into the same-day grocery delivery business which means putting warehouses in every state with a significant metro. Therefore, Amazon knows it will eventually have to collect sales tax in almost every state. So now, Amazon has changed its strategy and has been lobbying for all online retailers to have to collect sales taxes to "level the playing field" i.e. all play on the field that Amazon has single-handedly created to work in its favor.