Article 1, Section 10, Clause 2

No State shall, without the Consent of the Congress, lay any Imposts or Duties on Imports or Exports, except what may be absolutely necessary for executing it's inspection Laws: and the net Produce of all Duties and Imposts, laid by any State on Imports or Exports, shall be for the Use of the Treasury of the United States; and all such Laws shall be subject to the Revision and Controul of the Congress.

1.Articles of Confederation, art. 6, 1 Mar. 1781
2.Tench Coxe to Virginia Commissioners, 13 Sept. 1786
3.James Madison, Preface to Debates in the, 1787
4.Records of the Federal Convention
5.Luther Martin, Genuine Information, 1788
6.Alexander Hamilton, Federalist, no. 32, 199--203, 2 Jan. 1788
7.Debate in Virginia Ratifying Convention, 15 June 1788
8.Gibbons v. Ogden
9.Brown v. Maryland
10.James Madison to Professor Davis, 1832
11.Joseph Story, Commentaries on the Constitution: 2:§§ 1013--15, 1029--30, 1049, 1833