[JURIST] The US Supreme Court [official website; JURIST news archive] issued opinions in two cases Monday. The Court ruled [opinion, PDF] 7-2 in Polar Tankers v. City of Valdez [Cornell LII backgrounder; JURIST report] that a municipal tax that falls exclusively on large vessels in the city’s harbor violates the Tonnage Clause (Art 1 § 10 cl 3) of the US Constitution [text]. The city of Valdez, Alaska, imposes a tax on oil tankers and other large vessels using its port to pick up and deliver crude oil. The Alaska Supreme Court upheld [opinion, PDF] the tax. Reversing the opinion below, Justice Stephen Breyer wrote:

As far as we can tell, then, Valdez applies a value-based personal property tax to ships and to no other property at all. It does so in order to obtain revenue for general city purposes. The tax, no less than a similar duty, may (depending upon rates) "ta[x] the consumption" of those in other states. It is consequently the kind of tax that the Tonnage Clause forbids Valdez to impose without the consent of Congress, consent that Valdez lacks.