Article 1, Section 9, Clause 6
Luther Martin, Maryland House of Delegates29 Nov. 1787Farrand 3:157--58
S: 9. By this Article Congress will obtain unlimitted power over all the Ports in the Union and consequently acquire an influence that may be prejudicial to general Liberty. It was sufficient for all the purposes of General Government that Congress might lay what Duties they thought proper, and those who did not approve the extended power here given, contended that the Establishment of the Particular ports ought to remain with the Government of the respective States; for if Maryland for instance should have occasion to oppose the Encroachments of the General Government--Congress might direct that all Vessels coming into this Bay, to enter and clear at Norfolk, and thereby become as formidable to this State by an exercise of this power, as they could be by the Military arrangements or Civil Judiciaries. That the same reason would not apply in prohibiting the respective States from laying a Duty on Exports, as applied to that regulation being exercised by Congress: in the latter case a revenue would be drawn from the productive States to the General Treasury, to t[?] ease of the unproductive, but particular States might be desirous by this method to contribute to the support of their Local Government or for the Encouragement of their Manufactures.
The Founders' Constitution
Volume 3, Article 1, Section 9, Clause 6, Document 2
The University of Chicago Press
Farrand, Max, ed. The Records of the Federal Convention of 1787. Rev. ed. 4 vols. New Haven and London: Yale University Press, 1937.
Easy to print version.