completely restructure the income tax system, and establish a flat rate system for all persons and corporations at 15%.

The people of the United States have a tax system that promotes cheating and evasion. We need a system that is fair to all people, and the only way to do that is to completely revamp the tax system. A flat rate tax for individuals and businesses/corporations would be the only fair way to do it. Corporations want to be treated as individuals, so should be taxed in the same manner. A 5% percent flat rate would lower taxes for most people, and equalize the burden with higher income people and corporations.
If you make the taxes mandatory at that rate, and the non-reporting of income a punishable offense, you can eliminate almost all of the paperwork that the IRS handles today. That agency could spend it's time ensuring that wages and income are properly reported and recorded.