Authority over every issue not enumerated, or assigned to Congress, is reserved for the individual states.
“The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.”
A lot of Law professors today, maybe even most, just do not understand the intent of the Constitution or they are dishonest by choice just like Bible professors who teach unsound doctrine. They are destroying the minds of good men by teaching that the Constitution is not the Supreme Law of the Land and that the Supremacy Clause precludes nullification. “Federal law trumps state law” is their rallying cry.