Social Security Tax (Edit: and Medicare Tax)

I would make the Social Security tax progressive, with no cap, and I would make all income subject to this tax. I would also eliminate the Earned Income Tax Credit because I would make the first 20,000 of income, per person, subject to a zero percent rate. The Social Security tax would have to be calculated on your 1040 return since you may not have had the correct amount withheld during the year. The tax would be based on your total income before adjustments, deductions and exemptions.

(Edit: The same would apply to the Medicare tax as well. The Medicare tax would be adjusted to cover the current shortfall.)