[Ghoulish Delight]

It's definitely not a new tax. Everyone up to this point has actually technically been required to pay the tax. But up to this point, the onus has been on the customer to report the purchase to California on your state tax return and do the right thing.

No one does it, and there's no way to enforce it. But forcing retailers to collect and pay it is not exactly creating a new tax.

The reason it was that way is because it raises difficult Constitutional questions regarding inter-state trade. Does California have the authority to do this? The justification is that having any small presence in California, even employees or affiliates, is enough to consider it in-state trade. That seems to be a tenuous definition and will likely be where the legal challenge comes from. Just because Amazon happens to pay some people that do work in California, it seems quite a stretch to treat a transaction that doesn't involve anyone within California (e.g., I buy from a reseller who's locate in Kentucky) as in-state commerce.