Article 1, Section 9, Clause 1

The Migration or Importation of such Persons as any of the States now existing shall think proper to admit, shall not be prohibited by the Congress prior to the Year one thousand eight hundred and eight, but a Tax or duty may be imposed on such Importation, not exceeding ten dollars for each Person.

1.Thomas Jefferson, Bill to Prevent the Importation of Slaves, 16 June 1777
2.Pirate v. Dalby
3.Records of the Federal Convention
4.Tench Coxe, An Examination of the Constitution, Fall 1787
5.A Federal Republican, 28 Oct. 1787
6.James Wilson, Pennsylvania Ratifying Convention, 3--4 Dec. 1787
7.A Countryman, 13 Dec. 1787
8.Luther Martin, Genuine Information, 1788
9.Joshua Atherton, New Hampshire Ratifying Convention, 1788
10.Debate in South Carolina House of Representatives, 16--17 Jan. 1788
11.Debate in Massachusetts Ratifying Convention, 18, 25--26, 30 Jan. 1788
12.James Madison, Federalist, no. 42, 281--82, 22 Jan. 1788
13.Consider Arms, Malichi Maynard, and Samuel Field, Reasons for Dissent, 16 Apr. 1788
14.Debate in Virginia Ratifying Convention, 15 June 1788
15.Debate in North Carolina Ratifying Convention, 26 July 1788
16.James Madison, Import Duty on Slaves, House of Representatives, 13 May 1789
17.House of Representatives, Slave Trade, 23 Mar. 1790
18.St. George Tucker, Blackstone's Commentaries 1:App. 290, 1803
19.John Jay to Elias Boudinot, 17 Nov. 1819
20.James Madison to Robert Walsh, 27 Nov. 1819
21.Walter Lowrie, Senate, 20 Jan. 1820
22.James Madison to James Monroe, 10 Feb. 1820
23.Charles Pinckney, House of Representatives, 14 Feb. 1820
24.Gibbons v. Ogden
25.The Antelope
26.James Kent, Commentaries 1:179--87, 1826
27.Hunter v. Fulcher
28.Joseph Story, Commentaries on the Constitution 3:§§ 1327--31, 1833