It is just a matter of time. The Supreme Court’s decision in South Dakota v. Wayfair, Inc., has paved the way for states to begin implementing a sales tax on online sales.
Well, actually, for most states online sales have still been subject to sales tax, only the consumer had to pay it to the state. The retailer/wholesaler only had to do it if they had a physical presence in the state. Now that physical presence requirement is no longer law.
South Dakota estimated it was losing $645 per year per person in sales tax revenue. If that number can be applied nationwide, a state like California could be leaving $25 billion or more on the table. States are not going to forgo that money.