***And since all states are equal then no one state has any more power to say that the compact is broken than any single state has to say it has been not.***
Which is why those states may stay in the union if they so please. If the federal government levied a 10% sales tax in Idaho, then the federal government would have a breach of contract with Idaho only. Why should the other states have a say in what Idaho does at that point?
***James Madison said that a rightful secession requires the consent of all parties involved.***
And yet secession is still not denied to the states.
***Anything else leads to the kind of conflict that doomed the confederacy in 1861.***
Right, because Lincoln HAD to invade the South and burn it to the ground.
***and to change status once allowed to join are powers denied to the states.***
To change as a state, not as a member of the union. It says nothing about whether they may leave or not, only if they can change their territory (either by junction of two or more or by erecting one state from the jurisdiction of an existing one).
Such a tax would be a clear violation of Article I of the Constitution, and Idaho would have recource through the court system.
Why should the other states have a say in what Idaho does at that point?
Because Idaho doesn't exist in a vaccuum, and actions she take can have a negative impact on the interests of other states. And the same Constitution that prevents Idaho from being levied with that tax also prevents Idaho from imposing on another state's interests.
And yet secession is still not denied to the states.
Secession without the consent of the other states is, as the Supreme Court ruled in 1869.
Right, because Lincoln HAD to invade the South and burn it to the ground.
The confederacy started the war when they bombarded Sumter.
To change as a state, not as a member of the union.
Both.