Opinion of the Court
representatives’ statements to the Yakamas would have led the Yakamas to understand that the treaty’s protection of the right to travel on the public highways included the right to travel with goods for purposes of trade. We consequently so construe the relevant treaty provision.
Third, to impose a tax upon traveling with certain goods burdens that travel. And the right to travel on the public highways without such burdens is, as we have said, just what the treaty protects. Therefore, our precedents tell us that the tax must be pre-empted. In Tulee, for example, we held that the fishing right reserved by the Yakamas in the treaty pre-empted the application to the Yakamas of a state law requiring fishermen to buy fishing licenses. 315 U. S., at 684. We concluded that “such exaction of fees as a prerequisite to the enjoyment of ” a right reserved in the treaty “cannot be reconciled with a fair construction of the treaty.” Id., at 685. If the cost of a fishing license interferes with the right to fish, so must a tax imposed on travel with goods (here fuel) interfere with the right to travel.
We consequently conclude that Washington’s fuel tax “acts upon the Indians as a charge for exercising the very right their ancestors intended to reserve.” Ibid. Washington’s fuel tax cannot lawfully be assessed against Cougar Den on the facts here. Treaties with federally recognized Indian tribes–like the treaty at issue here–constitute federal law that pre-empts conflicting state law as applied to off-reservation activity by Indians. Cf. Mescalero Apache Tribe v. Jones, 411 U. S. 145, 148–149 (1973).
B
Again, we are not convinced by the arguments raised to the contrary. The Chief Justice concedes that “the right to travel with goods is just an application of the Yakamas’ right to travel.” Post, at 2 (dissenting opinion); see also ibid. (“It ensures that the Yakamas enjoy the same privi-
