Thomas, J., concurring in judgment
ternal quotation marks omitted). Rather, it “normally depends on the second sovereign’s law” as a matter of comity. Ibid. (internal quotation marks omitted). Because no federal law accords tribes sovereign immunity in federal court, petitioners lack immunity in this federal case.
Moreover, even if federal courts could afford immunity to tribes as a matter of comity, comity considerations would not help petitioners. “Even with respect to fully sovereign foreign nations, comity has long been discarded as a sufficient reason to grant immunity for commercial acts”—like those at issue here. Id., at 817 (emphasis added). And, far from furthering comity principles, recognizing immunity for off-reservation commercial acts “represents a substantial affront to a different set of sovereigns—the States.” Ibid. When a tribe engages in off-reservation commercial activity, “it necessarily acts within the territory of a sovereign State.” Id., at 818. Thus, to grant tribes a unique and unjustified immunity from both federal and state jurisdiction for commercial acts committed on a State’s territory “aggravate[s] relationships between States and tribes throughout the country.” Id., at 818–819. Accordingly, any common-law immunity that petitioners possess cannot support their claim to immunity in federal court for their off-reservation commercial conduct.
The Court’s tribal immunity doctrine is also out of step with more recent decisions. In Franchise Tax Bd. of Cal. v. Hyatt, 587 U. S. ___ (2019), the Court recognized that the 50 States possess a unique form of immunity that applies of its own force in the courts of sister States, id., at ___–___ (slip op., at 7–16), as well as those of the Federal Government, id., at ___ (slip op., at 12) (collecting cases). This immunity stems from the Constitution itself and belongs only to the 50 States through their ratification of the Constitution or admission to the Union on an equal footing with the original States. See Alden v. Maine, 527 U. S. 706, 713
