Page:Franchise Tax Board of California v. Hyatt.pdf/2

2 the idea that the States maintained sovereign immunity vis-à-vis each other in the same way that foreign nations do. Pp. 4–5.

(3) State sovereign immunity in another State’s courts is integral to the structure of the Constitution. The problem with Hyatt’s argument—that interstate sovereign immunity exists only as a matter of comity and can be disregarded by the forum State—is that the Constitution affirmatively altered the relationships between the States so that they no longer relate to each other as true foreign sovereigns. Numerous provisions reflect this reality. Article I. divests the States of the traditional diplomatic and military tools that foreign sovereigns possess. And Article IV. imposes duties on the States not required by international law. The Constitution also reflects alterations to the States’ relationships with each other, confirming that