Polar Tankers, Inc. v. City of Valdez, Alaska
The Supreme Court struck down a Valdez, Alaska, personal property tax that in practice applied almost exclusively to large oil tankers, ruling that it amounted to an unconstitutional tax on the privilege of entering the city's port.
Because the tax was closely tied to a ship's cargo capacity and wasn't matched by similar taxes on other property in the city, the Court held it violated the Constitution's Tonnage Clause, which bars states from taxing vessels for using their ports without Congress's permission.
“This case lies at the heart of what the Tonnage Clause forbids.”
The majority's summary conclusion that Valdez's tax was exactly what the Clause was meant to prohibit.
How it got here: An Alaska trial court struck the tax on other grounds; the Alaska Supreme Court reversed and upheld the tax; Polar Tankers asked the U.S. Supreme Court to review that ruling.
The Case in Depth
What happened
Valdez, Alaska adopted a personal property tax on large boats and vessels, with exceptions that limited it mostly to big oil tankers. Polar Tankers, a ConocoPhillips subsidiary whose ships carried crude oil from Valdez's port to refineries in other states, sued, arguing the tax was really an illegal charge for using the port and that its method of calculating tax owed was also unconstitutional.
The question before the Court
Could a city tax mostly aimed at large oil tankers count as an illegal "duty of tonnage" that only Congress can allow a state to impose?
Why it matters
Port cities that want to tax ships passing through or docking in their harbors must be careful not to design taxes that single out vessels the way Valdez did. The ruling limits how municipalities near busy shipping routes, especially oil ports, can raise revenue from ships without running afoul of a two-century-old constitutional limit on state and local taxing power.
What changes now
The case returns to the Alaska Supreme Court for further proceedings consistent with the ruling that the tax is unconstitutional. Valdez can no longer collect this tax as structured, though it may attempt to redesign its tax scheme to apply more evenly to other property. The decision is a final merits ruling on the Tonnage Clause question, though the Commerce Clause and Due Process Clause arguments Polar Tankers raised were left unresolved.
What this does not decide
The Court did not decide whether a truly evenhanded property tax applied equally to ships and other property would be constitutional, nor did it resolve Polar Tankers' separate Commerce Clause and Due Process Clause challenges to how the tax was calculated. Justice Alito's and the dissent's disagreement over this point shows the ruling is narrower than a blanket ban on all ship taxes.
Concurrences and dissents
Concurrence in part — Justice Roberts
Chief Justice Roberts agreed the tax was unconstitutional but would have ended the analysis simply because the tax was a duty of tonnage, full stop. He rejected the plurality's approach of comparing the tax to other city taxes, arguing that an unconstitutional charge on maritime commerce cannot become lawful just because it is bundled with other, unrelated taxes.
Concurrence in part — Justice Alito
Justice Alito joined the Court's opinion except for the part suggesting the tax might be valid if applied evenly to other personal property. He wrote separately to make clear he was not endorsing that idea, since he did not think it necessary to decide whether an evenhanded property tax on vessels would satisfy the Tonnage Clause.
Dissent — Justice Stevens
“The Tonnage Clause prohibits the States and their political subdivisions from charging ships for the privilege of using their ports. Because this case does not involve such a charge, I respectfully dissent.”Stevens's opening statement explaining why he believed the tax was a legitimate property tax, not a port-entry charge.
Justice Stevens argued the tax was a legitimate, value-based property tax on ships that had established a taxable presence in Valdez, not a disguised port-entry charge. He contended the majority wrongly conflated a ship's value with its cargo capacity, and that even under the majority's own test, Valdez taxed enough other property (mobile homes and oil-related equipment) to satisfy any 'same manner' requirement.
How the Court got there
The legal reasoning, step by step
- The Court applied the Tonnage Clause, a constitutional rule barring states from taxing ships for the privilege of entering, trading in, or lying in a port without Congress's consent, interpreting it broadly to cover any charge that functions this way regardless of its label.
- The Court found the Valdez tax fell within this prohibition because it applied almost exclusively to oil tankers, exempted nearly all other personal property, and its amount tracked a ship's carrying capacity, which is closely tied to tonnage.
- Turning to the city's defense that ship property taxes are permissible if applied 'in the same manner' as other property taxes, the plurality read this to mean a city taxing ships must also impose meaningfully similar taxes on other kinds of business property to avoid using its port position to disadvantage out-of-state interests.
- Applying that standard, the Court found Valdez taxed almost no other personal property in a comparable way—exempting vehicles, aircraft, and machinery, and taxing mobile homes only when treated as real property—so the ship tax lacked the safeguards that make ordinary property taxes constitutional.
- The Court also rejected Valdez's claim that its ship tax was simply part of a broader oil-property tax scheme, finding the two taxes differed significantly in who set rates, valued property, and collected revenue.
- Concluding that the tax functioned as a disguised charge for port access rather than an ordinary, evenhanded property tax, the Court held it unconstitutional under the Tonnage Clause without needing to reach Polar Tankers' separate Commerce Clause and Due Process Clause arguments.
Doctrinal impact
Cases affected by this decision
Distinguishes State Tonnage Tax Cases (12 Wall. 204)
The Court found this case's rule allowing value-based property taxes on ships did not save Valdez's tax, which failed the 'same manner' requirement.
Reaffirms Transportation Co. v. Wheeling (99 U. S. 273)
The Court relied on Wheeling's rule that ship property taxes must be imposed the same way as taxes on other property to find Valdez's tax invalid.