From the accepted doctrine that the United States is a government of delegated powers, it follows that those not expressly granted, or reasonably to be implied from such as are conferred, are reserved to the states, or to the people. To forestall any suggestion to the contrary, the Tenth Amendment was adopted. The same proposition, otherwise stated, is that powers not granted are prohibited [emphasis added]. United States v. Butler, 1936.
Cruz referred to the 10th Amendment as the fundamental statement in the Bill of Rights that the powers not given to the federal government are reserved to the states or to the people.
That means, he added, that as the Framers put it, the powers of the federal government are few and defined.