No. 109 Filed 10 May 1972 1. Taxation 9.5 — taxes on exports or imports — U.S. Constitution The purpose of Art. I, 10[2.] of the U.S. Constitution, prohibiting a state tax on imports, is to prevent the coastal states, and other states through which imports must pass, from levying a tax on imports before they reach their destination, so as to impede the free flow of goods between the states, and so as to prevent encroachment by the state upon taxing powers reserved exclusively to the national government