What does separation of powers mean to you?
Read 10th Amendment.
10th Amendment: 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.
Again, given that the states have never amended the Constitution to delegate to Congress the specific powers to establish most federal taxing and spending programs established since FDR's New Deal programs, also including abortion, euthanasia, banking, environmental protection, agriculture, healthcare, etc., the Founding States made the 10th Amendment to clarify that government powers to regulate such things are automatically reserved uniquely to the states.
Justice John Marshall had further officially clarified that Congress's is prohibited from laying taxes in the name of such issues, essentially any issue which Congress cannot justify under its Section 8, Article I-limited powers.
"Congress is not empowered to tax for those purposes which are within the exclusive province of the States." --Justice John Marshall, Gibbons v. Ogden, 1824.