I do believe I said as much:
Obviously, if a power that's forbidden to the federal government is involved or if the federal government oversteps its authority, federal law isn't supreme in that area.
You say:
John Marshall stated that a delegated authority may be recalled, the states are the contracting parties, not the federal government, and it's a union of states not a fixed number, nowhere does it state that a party may not leave.
It looks like that's precisely what Marshall did not say in McCullough vs. Maryland (1819). So far as I understand him he allowed that the People could modify the Constitution, but that the federal government was not a mere creature of the states. It's a very subtle point, but that's my understanding.
Inasmuch as he and others have pointed out elsewhere that the Constitution, and perforce the Union, were created by the People, and that moreover the States are the People in their corporate form, then therefore his point amounts to a distinction without a difference. One suspects that Marshall is playing games here, trying to elevate the Government to sovereignty again -- a favorite preoccupation of all the Hamiltonians from the moment the guns fell silent at Yorktown.