The 16th Amendment was required because the original Constitution prohibited such immoral schemes as income tax (Article I Section 9 had to be amended).
This was the brainchild of American Progressives and is the cornerstone of centralized government planning and control. Now the government attempts to control economic behavior by creating the byzantine rate structures, exceptions, exemptions, credits, deductions, etc.
Get the government's hands out of our pockets! Read HR 25. If you agree, contact your congressman (especially if s/he sits on the Ways and Means Committee) and urge them to recommend the bill for a floor vote. it has 59 or more sponsors this session but has been stuck in committee for the past 20 freaking yrs.