The Founders who designed our Constitution sought to balance the power of the federal government against the states in order to keep both in check. The national government was thus originally prohibited from collecting taxes from individuals. Article I, Section 9 of the Constitution states: "No capitation, or other direct Tax, shall be laid unless in Proportion to the Census or Enumeration." This meant that the federal government could collect revenue from the states according to population, but had to leave the methods of collection to them. The federal government was to collect revenue in other, less intrusive ways (tariffs, excise taxes, consumption taxes) so as to limit the amount of money it could raise by its own authority.
It's time to repeal the 16th Amendment.