Cap tax deductions at 28% for the wealthiest Americans. The rich are able to get much bigger tax breaks for the same tax deductions taken by the middle class.
For example, a wealthy family living in a McMansion gets a much bigger tax deduction on the interest on their large mortgage than a middle-class family gets on the interest on their small mortgage on a two-bedroom house.
President Obama proposed to limit the tax break on deductions that the richest 3% can take to 28 cents on the dollar. In other words, the rich would get the same tax benefit per dollar of deductions as a household in the 28% tax bracket, but not more (as they do now) at the higher 39.6% bracket.
This would raise $500 billion over 10 years.