The absence of a black-and-white, judicially defined, "limiting principle" does not imply that a Constitutional power is "unlimited". It just means that there may be no reason to have a black-and-white, judicially defined, "limiting principle".
Much of the Constitution's language is contestable, and it might even change over time. Congress can do anything necessary and proper to execute it's powers. What is considered necessary and proper may indeed change. It doesn't mean the power is unlimited. In any time what is improper and unnecessary is not allowed to the Congress.
Sorry if that doesn't always fit into a nice tidy judicial test.
Similarly, a lot of the penal practices of the eighteenth century would probably be considered "cruel and unusual" today. That term is contestable too. That's life. Nailing that down in a "test" is doomed to failure.
Who says limits on the state have to come in the form of a judicial test? Sounds like something a lawyer would come up with. I see no grounds for that claim, though.
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