“ The Court believes that this “course of perform­ance” demonstrates that, once the Commission turned off its monetary spigot, North Carolina was no longer re­quired to do anything further. Ante, at 14–15. But why? If I advance my builder half the cost of a building, I have not thereby promised to advance him the whole cost. This is particularly true when the contract says I am responsi­ble for none of the cost of the building. At the very least, something more in the circumstances would have to show that additional expenditure had become a reasonable expectation. ”

“ Unlike the Court, however, I believe that North Carolina breached the Southeast Interstate Low-Level Radioactive Waste Management Compact (Compact) when it sus­pended its efforts toward building a waste disposal facility. (THE CHIEF JUSTICE joins all but Parts II–D and III–B of the Court’s opinion.)
Article 5 (C) is the critical term of the Compact. It states:
“Each party state designated as a host state for a re­gional facility shall take appropriate steps to ensure that an application for a license to construct and op­erate a facility . ”

“ More to the point, if a builder promises that he will “take appro­priate steps to ensure” that a customer will be able to move into a new home in two years, and then does nothing at all, has the builder not broken his promise? ”

“ For purposes of rejecting this argument, it is sufficient to note—as the Court does—that the Compact permits any State to withdraw; imposes no limitation on this right; and explicitly provides that the Compact shall not be construed to abridge the sovereign rights of any party State. See ante, at 20–21. Federalism concerns also counsel reluctance to find that a State has implicitly restricted its sovereignty in such a manner. ”

“ It is therefore impossible for the Court to hear private claims against a nonconsenting State without expanding “our judicial power over the controversy.” Arizona, supra, at 614. Sovereign immunity is a limitation on that power. ”

“ Most importantly, the subsequent development of our sovereign immunity jurisprudence has only undermined Arizona’s already weak foundations. We recognized in Alden v. Maine, 527 U. S. 706, 718 (1999) , that the Constitution left intact the States’ pre-existing “immunity from private suits”; as the Eleventh Amendment confirms, the States did not “ ‘surrender . . . this immunity in the plan of the convention.’ ” Id., at 717 (quoting The Federalist No. 81, p. 487 (C. Rossiter ed. 1961) (A. Hamilton) ) ”

“ Kidd, 254 U. S. 433, 439 (1921) (“ [T] reaties are to be interpreted upon the principles which govern the interpretation of contracts . . . with a view to making effective the purposes of the high contracting parties”) ”