They conjured up nothing. The decision perfectly aligned with supreme court decisions about the union and the constitution made before the civil war.
"The Constitution of the United States was ordained and established not by the States in their sovereign capacities, but emphatically, as the preamble of the Constitution declares, by 'the people of the United States." Joseph Story Martin v Hunter 1821
"The people made the constitution, and the people can unmake it. It is the creature of their will, and lives only by their will. But this supreme and irresistible power to make or to unmake, resides only in the whole body of the people; not in any sub-division of them. The attempt of any of the parts to exercise it is usurpation, and ought to be repelled by those to whom the people have delegated their power of repelling it." Chief Justice John Marshall Cohens v Virginia 1821
Gibbons v Ogden, 1824 - "In every such case, the act of Congress or the treaty is supreme, and the law of the State, though enacted in the exercise of powers not controverted, must yield to it."
Fletcher v Peck, 1810 - "Union has a constitution the supremacy of which all acknowledge, and which imposes limits to the legislatures of the several states, which none claim a right to pass"
US v Fries, 1800 - "That if a body of people, conspire and meditate an insurrection to resist or oppose the execution of any statute of the United States by force, they are only guilty of a high misdemeanor; but if they proceed to carry such intention into execution by force, that they are guilty of the treason of levying war; and the quantum of the force employed neither lessens or increases the crime -- whether by one hundred or one thousand persons is wholly immaterial"