| Washington did not pass additional laws. It was the Supreme Court's South Dakota v Wayfair ruling: https://www.supremecourt.gov/opinions/17pdf/17-494_j4el.pdf https://en.wikipedia.org/wiki/South_Dakota_v._Wayfair,_Inc. Prior to this ruling, if you were a merchant in state A and you mailed something to someone in State B, you were not considered to have an economic nexus in state B, and hence state B had no jurisdiction over you to enforce sales tax collection. Previous definitions of economic nexus involved having physical buildings or employees operating within a jurisdiction's boundaries. South Dakota v Wayfair said that mailing something to a customer established economic nexus in the customer's jurisdiction, hence the merchant now has to register as a business in the customer's jurisdiction and collect applicable sales taxes and follow all the laws of that jurisdiction. The whole ruling is weird though, because the justification came down to it's messing up the order of things, and since Congress can't be bothered to fix it with legislation, the Courts have to make up stuff to prolong the status quo. |