By David Mittelstadt and David Hunter (July 6, 2018, 11:54 AM EDT) -- For over 50 years, interstate vendors have relied on a bright-line standard establishing that they did not have to collect destination-state sales taxes in respect of interstate sales unless they had a physical presence there. The physical presence standard was initially established back in 1967 by the United States Supreme Court's decision in National Bellas Hess Inc. v. Department of Revenue of Illinois.[1] That case was decided both on due process and commerce clause grounds. The physical presence standard endured through the court's decision in Quill Corp. v. North Dakota,[2] decided in 1992, and all the way to June 21, 2018. During that period, the constitutional basis for the establishment of the physical presence standard morphed somewhat, but as a standard it remained intact. (By the time Quill came around, the court decided that due process did not mandate physical presence, but still maintained that standard largely on dormant commerce clause grounds)....