https://phys.org/news/2018-06-high-court-online-shoppers-sales.html

On Thursday, the Supreme Court agreed to overturn those decisions in a 5-4 ruling. The cases the court overturned said that if a business was shipping a customer's purchase to a state where the business didn't have a physical presence such as a warehouse or office, the business didn't have to collect the state's sales tax. Customers were generally responsible for paying the sales tax to the state themselves if they weren't charged it, but most didn't realize they owed it and few paid.

Justice Anthony Kennedy wrote that the previous decisions were flawed.