The Mississippi State Tax Commission (D) informed Complete (P) that it was being assessed taxes and interest totaling $122,160.59 for the sales of transportation services during the three-year period from August 1, 1968, through July 31, 1971. P is a Michigan corporation engaged in the business of transporting motor vehicles by motor carrier for General Motors Corporation. General Motors assembles outside Mississippi vehicles that are destined for dealers within the State. The vehicles are then shipped by rail to Jackson, Miss., where, usually within 48 hours, they are loaded onto P's trucks and transported to the Mississippi dealers. P paid the assessments under protest and instituted the present refund action in the Chancery Court of the First Judicial District of Hinds County. P claimed that its transportation was but one part of an interstate movement and that the taxes assessed and paid were unconstitutional as applied to operations in interstate commerce. The issue is whether this state tax runs afoul of the Commerce Clause, U.S. Const., Art. I, 8, cl. 3, when it applies the tax it imposes on 'the privilege of . . . doing business' within the State to a party's activity in interstate commerce. P did not allege that its activity which Mississippi taxes does not have a sufficient nexus with the State; or that the tax discriminates against interstate commerce; or that the tax is unfairly apportioned; or that it is unrelated to services provided by the State. P does not claim that discrimination or undue burdens exist in fact. P's attack is based solely on decisions of this Court holding that a tax on the 'privilege' of engaging in an activity in the State may not be applied to an activity that is part of interstate commerce. The Chancery Court, in an unreported opinion, sustained the assessments. The Mississippi Supreme Court affirmed. It held that P has a large operation in this State. It is dependent upon the State for police protection and other State services the same as other citizens. It should pay its fair share of taxes so long, but only so long, as the tax does not discriminate against interstate commerce, and there is no danger of interstate commerce being smothered by cumulative taxes of several states. There is no possibility of any other state duplicating the tax involved in this case. The Supreme Court granted certiorari.