Yeah? Well, the next time the U.S. abrogates a treaty its chief executive has signed, like, oh, Kyoto, say, try suing the United States Government to demand compliance, on grounds that the other signatories hadn't given the United States permission to withdraw. See what happens.
The state laving impacts the wellbeing of the states remaining.
That happens a lot, when sovereignty is involved. The imperial Russian government still owes some American estates a lot of money. Heard about any collections lately?
I happen to believe that they should have a say in the matter.
Operative word, "believe". You would be incorrect, however.
As I pointed out above, the States retained rights and powers of sovereignty when they ratified the Constitution, and you cannot produce any clause of the Constitution that abrogates them. The exercise of rights and powers shows why they are called that quite precisely because other parties that may be affected by the exercise have no right or power to interfere, suspend, or block the exercise of same.
The States retain certain rights and powers even as members of the Union: Ohio's supreme court adjudicated an eminent-domain case the other day, coming to a resolution diametrically opposed to Associate Justice Souter's opinion last year on the same subject; but Ohio's case was brought under Ohio's constitution, and so that case is not subject to federal review. This would be true even though the Ohio court had reached a conclusion inimical to the interests of an out-of-state development company whose management might have expected Ohio to follow Souter's reasoning to Souter's holding. The out-of-state developers couldn't now sue Ohio for holding without regard to the effect on the out-of-state developers' interest. Neither could their home state, despite a possible loss of tax revenue, in-state wages, etc., which might ensue from the Ohio court's decision.
The dictionary defines sovereignty as supreme power especially over a body politic or freedom from external control. Obviously you have your own definition of the word. How about letting us in on what it is?