Import-export clause refers to a provision provided by the U.S. Constitution prohibiting states from taxing imports or exports. However, the U.S. Supreme Court has given a broad interpretation of this clause. Under this clause, states are allowed to tax imports as long as the tax does not discriminate in favor of domestic goods.
According to USCS Const. Art. I, § 10, Cl 2, the following are the purposes of import-export clause :
1.Maintaining federal uniformity in foreign commercial relations;2.Preventing the diversion to the states revenue generated by imported goods;and
3.Maintaining harmony among the states by preventing states from taxing goods flowing through seaboard state ports to or from other states.