The Port Preference Clause

No Preference shall be given by any Regulation of Commerce or Revenue to the Ports of one State over those of another; nor shall Vessels bound to, or from, one State, be obliged to enter, clear, or pay Duties in another.

—Nelson Lund

Introduction

The Constitution includes several provisions designed to prevent the federal government from treating the states inequitably, especially with respect to taxation and the regulation of commerce. The Uniformity Clause, for example, requires that federal duties, imposts, and excises be uniform throughout the United States. (See Essay No. 41.) Similarly, the Port Preference Clause forbids Congress from granting special privileges to the ports of certain states or to funnel shipping through ports other than those in the state of its origin or destination. Like the Uniformity Clause, with which it was initially joined at the Constitutional Convention,¹ the Port Preference Clause was meant to interfere with the natural tendency of legislatures to become instruments through which powerful special interests injure their politically weaker rivals.

The Constitutional Convention

The impetus for the Port Preference Clause came from the Maryland delegation, whose members were especially worried that vessels bound to or from the port of Baltimore might be required to stop in Virginia.² Some other delegates objected that Congress should not have its hands tied lest it be unable to deal adequately with problems such as smuggling on long rivers like the Delaware.³ The issue was referred to an eleven-member committee on trade, which recommended language nearly identical to the final versions of this clause and the Uniformity Clause.⁴ There was no further recorded debate at the Convention.

The Ratification Debates

Maryland’s Luther Martin, who became a leading Anti-Federalist, remained dissatisfied. Martin objected to the Port Preferences Clause during a lengthy address to his state’s legislature. He objected that Congress might easily violate the spirit of the Port Preference Clause, perhaps by limiting Maryland to one inconvenient port of entry such as Georgetown, which is situated near the point where the Potomac ceases to be navigable. This would effectively require shipping bound to or from other ports, such as Baltimore, to clear and enter at a Virginia port.⁵ Despite Martin’s efforts, however, the clause did not become a significant point of contention in the ratification debates.

Judicial Precedent

Notwithstanding the broad language of the Port Preference Clause, the U.S. Supreme Court has construed it very narrowly. Congress is allowed to grant enormous “incidental” preferences to the ports of certain states. For example, Congress can make improvements, such as dredging, in one place but not another; it can also create obstructions, such as bridges, in a disfavored place rather than a favored place.⁶ The Court has indicated that the clause would be violated only by overt discrimination between all the ports of one state and those of another.⁷ Yet even this prohibition is essentially toothless. The Court has read the Clause to allow Congress to impose a tax that affected all the ports of some states and no ports in some others.⁸ The Federal Circuit upheld a tax exemption that applied only to ports in Alaska and Hawaii.⁹

A dissent in the leading Supreme Court case objected that the majority’s interpretation rendered the clause a dead letter.¹⁰ More recently, Justice Clarence Thomas suggested in a concurrence that a natural reading of the clause “prohibits Congress from using its commerce power to channel commerce through certain favored ports.”¹¹ As the case law stands, however, Congress is only on its honor to comply with the spirit of the clause by refraining from politically motivated favoritism that distorts the natural economic competition among American ports.

Open Questions

• Might the Court someday revisit its narrow interpretation of the Port Preference Clause as Justice Thomas suggested?¹²
• If the Supreme Court were to reinterpret the Port Preference Clause to impose a broader uniformity constraint on Congress, might it also reinterpret the Commerce Clause to ban non-uniform commercial regulations more generally?¹³

1. 2 Farrand’s 410. ↩︎
2. Id. at 417–18. ↩︎
3. Id. at 418, 480–81. ↩︎
4. Id. at 418, 434. ↩︎
5. 3 Farrand’s 172, 213–14. ↩︎
6. Pennsylvania v. Wheeling & Belmont Bridge Co., 59 U.S. 421, 433–34 (1856) (Wheeling Bridge II); South Carolina v. Georgia, 93 U.S. 4, 12–13 (1876). ↩︎
7. Wheeling Bridge II, 59 U.S. at 435. ↩︎
8. Augusta Towing Co., Inc. v. United States, 5 Cl. Ct. 160, 165–66 (1984). ↩︎
9. Thomson Multimedia Inc. v. United States, 340 F.3d 1355, 1364–66 (Fed. Cir. 2003). ↩︎
10. Wheeling Bridge II, 59 U.S. at 443–44 (McLean, J., dissenting). ↩︎
11. United States v. Lopez, 514 U.S. 549, 587 (1995) (Thomas, J., concurring). ↩︎
12. Sam Heavenrich, The Neglected Port Preference Clause and the Jones Act, 132 Yale L.J. 559 (2022). ↩︎
13. Thomas B. Colby, Revitalizing the Forgotten Uniformity Constraint on the Commerce Power, 91 Va. L. Rev. 249 (2005). ↩︎