I think the problem is that they want to apply a sales tax to anyone that is referred to Amazon /worldwide/ by a Connecticut referrer. That is why Amazon argues

I think the problem is that they want to apply a sales tax to anyone that is referred to Amazon /worldwide/ by a Connecticut referrer. That is why Amazon argues that it is unconstitutional. If it were simply taxing Connecticut consumers it would be similarly complicated, but I think there is more constitutional grounds for this. I'd have to check. It's not like Amazon is going to pull out of the state.